Dermal tumors and proliferations US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Dermal tumors and proliferations. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Dermal tumors and proliferations US Medical PG Question 1: A 57-year-old post-menopausal woman comes to the physician because of intermittent, bloody post-coital vaginal discharge for the past month. She does not have pain with intercourse. Eleven years ago, she had LSIL on a routine Pap smear and testing for high-risk HPV strains was positive. Colposcopy showed CIN 1. She has not returned for follow-up Pap smears since then. She is sexually active with her husband only, and they do not use condoms. She has smoked half a pack of cigarettes per day for the past 25 years and does not drink alcohol. On speculum exam, a 1.4 cm, erythematous exophytic mass with ulceration is noted on the posterior wall of the upper third of the vagina. Which of the following is the most probable histopathology of this mass?
- A. Basal cell carcinoma
- B. Melanoma
- C. Adenocarcinoma
- D. Sarcoma botryoides
- E. Squamous cell carcinoma (Correct Answer)
Dermal tumors and proliferations Explanation: ***Squamous cell carcinoma***
- The patient's history of **LSIL** with **high-risk HPV** and **non-adherence to follow-up Pap smears** strongly suggests a progression to squamous cell carcinoma.
- **Smoking** is a significant risk factor for SCC, and the description of an **erythematous exophytic mass with ulceration** is consistent with this diagnosis.
*Basal cell carcinoma*
- This is a common skin cancer, but it is **extremely rare in the vagina**, typically occurring in sun-exposed areas.
- While it can manifest as an ulcerated lesion, the risk factors and location do not align with this patient's presentation.
*Melanoma*
- Although **vaginal melanoma** can occur, it is rare and typically presents as a **pigmented lesion**, which is not described.
- The patient's risk factors (HPV, smoking) are not primary drivers of melanoma development.
*Adenocarcinoma*
- **Vaginal adenocarcinoma** is rare and often associated with **diethylstilbestrol (DES) exposure** in utero, which is absent in this case.
- While an exophytic mass can occur, the strong history of **HPV-related dysplasia** points away from adenocarcinoma.
*Sarcoma botryoides*
- This is a rare form of **rhabdomyosarcoma** and typically presents in **infants and young children** as a grapelike mass protruding from the vagina.
- It is not seen in post-menopausal women and is histologically distinct from the likely HPV-related malignancy.
Dermal tumors and proliferations US Medical PG Question 2: A 59-year-old man with chronic hepatitis C infection comes to the physician because of a 2-week history of ankle pain and nonpruritic skin lesions on his legs. He does not recall recent trauma or injury. He has not received treatment for hepatitis. Examination shows diffuse, violaceous lesions on both lower extremities. The lesions are 4–7 mm in size, slightly raised, and do not blanch with pressure. These skin lesions are best classified as which of the following?
- A. Ecchymoses
- B. Petechiae
- C. Hemangioma
- D. Spider angioma
- E. Purpura (Correct Answer)
Dermal tumors and proliferations Explanation: **Purpura**
- **Purpura** are skin lesions caused by **extravasation of red blood cells** into the skin, appearing as violaceous, non-blanching spots that are typically 2 mm to 1 cm in size. The patient's lesions, measuring 4–7 mm and being non-blanching, fit this description.
- In a patient with **chronic hepatitis C**, purpura, especially when accompanied by **arthralgia** (ankle pain), is highly suggestive of **cryoglobulinemic vasculitis**, which is a common extrahepatic manifestation of hepatitis C.
*Ecchymoses*
- **Ecchymoses** are larger areas of superficial bleeding into the skin, typically greater than 1 cm in diameter, commonly known as **bruises**.
- While they are violaceous and non-blanching, the described lesions are smaller (4–7 mm) and appear as diffuse, slightly raised spots rather than typical bruises from trauma.
*Petechiae*
- **Petechiae** are very small, pinpoint (typically <2 mm) red or purple spots caused by minute hemorrhages into the skin.
- The patient's lesions are larger (4–7 mm) than petechiae, making this option less likely.
*Hemangioma*
- A **hemangioma** is a benign tumor of blood vessels, often appearing as a raised, red or bluish lesion that typically does not resolve spontaneously in adults.
- These lesions are usually permanent vascular malformations, whereas the patient's presentation suggests a more acute onset of extravascular bleeding.
*Spider angioma*
- A **spider angioma** is a cluster of dilated capillaries radiating from a central arteriole, resembling a spider. They **blanch with pressure** and are often associated with liver disease (due to estrogen excess).
- The patient's lesions are described as **non-blanching** and diffuse, not resembling the characteristic "spider" appearance, and are indicative of extravasated blood rather than dilated vessels.
Dermal tumors and proliferations US Medical PG Question 3: A 6-year-old boy is brought to the physician by his parents because of right lower extremity weakness, worsening headaches, abdominal pain, dark urine, and a 5-kg (11-lb) weight loss for the past 2 months. His teachers report that he has not been paying attention in class and his grades have been worsening. He has a history of infantile seizures. Physical examination shows a palpable abdominal mass and left costovertebral angle tenderness. Neurological exam shows decreased strength of the right lower limb. He has several acne-like angiofibromas around the nose and cheeks. Further evaluation is most likely to show which of the following?
- A. Subependymal giant cell astrocytoma
- B. Vestibular schwannoma
- C. Pheochromocytoma
- D. Lisch nodules
- E. Renal angiomyolipomas (Correct Answer)
Dermal tumors and proliferations Explanation: ***Renal angiomyolipomas***
- The patient's presentation of **infantile seizures**, **facial angiofibromas (adenoma sebaceum)**, and multiple organ system involvement strongly indicates **tuberous sclerosis complex (TSC)**.
- The **palpable abdominal mass**, **costovertebral angle tenderness**, and **dark urine (hematuria)** are key findings pointing to renal pathology.
- **Renal angiomyolipomas** occur in approximately **80% of TSC patients** and are the most common renal manifestation of the disease.
- These benign tumors contain blood vessels, smooth muscle, and fat, and can cause flank pain, hematuria, and palpable masses, all present in this patient.
- Given the prominent renal symptoms, further evaluation with imaging (CT or ultrasound) would most likely reveal renal angiomyolipomas.
*Subependymal giant cell astrocytoma*
- While **subependymal giant cell astrocytomas (SEGAs)** are indeed associated with TSC and could explain the neurological symptoms (headaches, weakness), they occur in only **10-20% of TSC patients**.
- The question asks what further evaluation is **most likely** to show - the prominent renal findings (palpable mass, CVA tenderness, hematuria) make renal imaging the most likely next step, which would reveal angiomyolipomas.
- SEGAs are a valid TSC manifestation but less likely than renal angiomyolipomas given the clinical presentation emphasizing renal symptoms.
*Vestibular schwannoma*
- **Vestibular schwannomas** are associated with **Neurofibromatosis type 2 (NF2)**, not tuberous sclerosis.
- These tumors typically present with hearing loss, tinnitus, and balance problems, none of which are described in this patient.
- The facial angiofibromas and infantile seizures clearly point to TSC, not NF2.
*Lisch nodules*
- **Lisch nodules** are iris hamartomas pathognomonic for **Neurofibromatosis type 1 (NF1)**.
- NF1 presents with café-au-lait spots, neurofibromas, and optic gliomas, not facial angiofibromas or the pattern seen here.
- This patient's constellation of findings is diagnostic of TSC, not NF1.
*Pheochromocytoma*
- **Pheochromocytomas** cause episodic hypertension, palpitations, headaches, and sweating due to catecholamine excess.
- While associated with genetic syndromes (MEN2, NF1, VHL), they are not a typical feature of tuberous sclerosis.
- The patient's symptoms and physical findings do not suggest pheochromocytoma, and there is no mention of hypertensive episodes or associated symptoms.
Dermal tumors and proliferations US Medical PG Question 4: A 23-year-old man comes to the physician for evaluation of decreased hearing, dizziness, and ringing in his right ear for the past 6 months. Physical examination shows multiple soft, yellow plaques and papules on his arms, chest, and back. There is sensorineural hearing loss and weakness of facial muscles bilaterally. His gait is unsteady. An MRI of the brain shows a 3-cm mass near the right internal auditory meatus and a 2-cm mass at the left cerebellopontine angle. The abnormal cells in these masses are most likely derived from which of the following embryological structures?
- A. Surface ectoderm
- B. Neural tube
- C. Neural crest (Correct Answer)
- D. Notochord
- E. Mesoderm
Dermal tumors and proliferations Explanation: ***Neural crest***
- The patient's symptoms (bilateral sensorineural hearing loss, facial weakness, unsteady gait, central masses) along with cutaneous lesions (soft, yellow plaques) are highly suggestive of **Neurofibromatosis type 2 (NF2)**.
- NF2 is characterized by **vestibular schwannomas** (acoustic neuromas) and other CNS tumors, which are derived from **Schwann cells**. Schwann cells, along with melanocytes and other peripheral nervous system components, originate from the **neural crest**.
*Surface ectoderm*
- The surface ectoderm forms structures such as the **epidermis**, hair, nails, and anterior pituitary.
- While the skin lesions are present, the primary tumors (schwannomas) are not derived from the surface ectoderm.
*Neural tube*
- The neural tube gives rise to the **central nervous system** (brain and spinal cord) and motor neurons.
- While the tumors affect the brain and cranial nerves, the specific cell type forming schwannomas (Schwann cells) does not originate directly from the neural tube.
*Notochord*
- The notochord induces the formation of the neural tube and eventually degenerates, contributing to the **nucleus pulposus** of the intervertebral discs.
- It is not involved in the pathogenesis or cellular origin of schwannomas.
*Mesoderm*
- The mesoderm gives rise to connective tissues, blood, bone, muscle, and most internal organs.
- While some tumors can have mesodermal origins, schwannomas are neuroectodermal in origin.
Dermal tumors and proliferations US Medical PG Question 5: An investigator studying the molecular characteristics of various malignant cell lines collects tissue samples from several families with a known mutation in the TP53 tumor suppressor gene. Immunohistochemical testing performed on one of the cell samples stains positive for desmin. This sample was most likely obtained from which of the following neoplasms?
- A. Squamous cell carcinoma
- B. Rhabdomyosarcoma (Correct Answer)
- C. Prostate cancer
- D. Endometrial carcinoma
- E. Melanoma
Dermal tumors and proliferations Explanation: ***Rhabdomyosarcoma***
- **Desmin** is an intermediate filament present in **muscle cells**, and its positive staining is a definitive marker for tumors of muscle origin
- A **rhabdomyosarcoma** is a malignant tumor of **skeletal muscle** differentiation, thus explaining the positive desmin staining.
*Squamous cell carcinoma*
- **Squamous cell carcinomas** are epithelial tumors that typically stain positive for **cytokeratin**, not desmin, as they originate from epithelial cells.
- They are characterized by features such as **intercellular bridges** and **keratinization**.
*Prostate cancer*
- **Prostate cancer** is an adenocarcinoma, meaning it's derived from glandular epithelial cells, and would stain positive for markers like **PSA (prostate-specific antigen)**, not desmin.
- This tumor type is characterized by glandular differentiation.
*Endometrial carcinoma*
- **Endometrial carcinomas** are adenocarcinomas of the uterine lining, derived from glandular epithelial cells, and would express **cytokeratins**, not desmin.
- Histologically, they show glandular structures and atypical endometrial cells.
*Melanoma*
- **Melanomas** are malignant tumors of melanocytes and would stain positive for markers such as **S-100**, **HMB-45**, and **Mart-1**, not desmin.
- These tumors originate from neural crest cells and are not muscle-derived.
Dermal tumors and proliferations US Medical PG Question 6: A 48-year-old man comes to the physician because of a skin lesion on his nose and in his mouth. The lesions have been gradually increasing in size and are not painful or pruritic. Two months ago, he was treated for esophageal candidiasis. Physical examination shows one pinkish-brown papule on the right wing of the nose and two similar nodular lesions on the hard palate and buccal mucosa. A biopsy of one of the lesions shows spindle-shaped endothelial cells and infiltration of lymphocytes, plasma cells, and macrophages. Which of the following is the most likely causal organism of this patient's condition?
- A. Mycobacterium avium complex
- B. Epstein-Barr virus
- C. Polyomavirus
- D. Human herpes virus 8 (Correct Answer)
- E. Poxvirus
Dermal tumors and proliferations Explanation: ***Human herpes virus 8***
- The presence of **pinkish-brown papules/nodules** on the skin and oral mucosa, along with a history of esophageal candidiasis (which suggests an **immunocompromised state**), is highly indicative of **Kaposi's sarcoma**.
- **Biopsy findings** of spindle-shaped endothelial cells and inflammatory infiltrate are characteristic features of Kaposi's sarcoma, which is caused by HHV-8.
*Mycobacterium avium complex*
- This infection usually presents with **systemic symptoms** like fever, night sweats, weight loss, and adenopathy, or gastrointestinal symptoms, rather than localized skin and oral lesions.
- Granulomas, not spindle cell lesions, would be expected on **biopsy**.
*Epstein-Barr virus*
- EBV is associated with various lymphoproliferative disorders and lymphomas, as well as **oral hairy leukoplakia** in immunocompromised patients.
- It does not typically cause the **vascular, nodular lesions** described here.
*Polyomavirus*
- Polyomaviruses (e.g., JC virus, BK virus) are associated with **progressive multifocal leukoencephalopathy** and **nephropathy** in immunocompromised patients.
- They do not cause these specific types of **skin and oral lesions**.
*Poxvirus*
- Poxviruses (e.g., molluscum contagiosum) cause **umbilicated papules** or extensive skin lesions but are not associated with the **vascular spindle cell proliferation** seen in Kaposi's sarcoma.
- The lesions caused by poxviruses have a different **histological appearance**.
Dermal tumors and proliferations US Medical PG Question 7: A 45-year-old man comes to the emergency department because of chills and numerous skin lesions for 1 week. He has also had watery diarrhea, nausea, and abdominal pain for the past 2 weeks. The skin lesions are nonpruritic and painless. He was diagnosed with HIV infection approximately 20 years ago. He has not taken any medications for over 5 years. He sleeps in homeless shelters and parks. Vital signs are within normal limits. Examination shows several bright red, friable nodules on his face, trunk, extremities. The liver is palpated 3 cm below the right costal margin. His CD4+ T-lymphocyte count is 180/mm3 (N ≥ 500). A rapid plasma reagin test is negative. Abdominal ultrasonography shows hepatomegaly and a single intrahepatic 1.0 x 1.2-cm hypodense lesion. Biopsy of a skin lesion shows vascular proliferation and abundant neutrophils. Which of the following is the most likely causal organism?
- A. Bartonella henselae (Correct Answer)
- B. Treponema pallidum
- C. HHV-8 virus
- D. Mycobacterium avium
- E. Candida albicans
Dermal tumors and proliferations Explanation: ***Bartonella henselae***
- The patient's presentation with **bright red, friable nodules** (consistent with **bacillary angiomatosis**) in an HIV-positive individual with a low **CD4+ count** strongly suggests infection with *Bartonella henselae*.
- **Hepatomegaly** and **intrahepatic lesions** further support disseminated bartonellosis, and skin biopsy showing vascular proliferation with **abundant neutrophils** is characteristic.
*Treponema pallidum*
- While *Treponema pallidum* (syphilis) can cause various skin lesions, the **rapid plasma reagin (RPR) test** was negative, making syphilis highly unlikely.
- Syphilitic lesions typically do not present as brightly friable nodules with prominent vascular proliferation and neutrophils characteristic of bacillary angiomatosis.
*HHV-8 virus*
- **HHV-8** is the causative agent of **Kaposi sarcoma**, which also presents with vascular lesions. However, Kaposi sarcoma lesions are typically **violaceous plaques or nodules** and histologically show spindle cells and extravasated red blood cells, not the prominent neutrophils seen here.
- The patient's clinical presentation, particularly the friable nature and specific histology, steers away from Kaposi sarcoma.
*Mycobacterium avium*
- *Mycobacterium avium* complex (MAC) can cause disseminated disease in HIV patients with low CD4 counts, often presenting with fever, weight loss, and gastrointestinal symptoms.
- However, MAC infection rarely causes specific nonpruritic, bright red, friable skin nodules like those described, and hepatic lesions would typically be granulomatous, not necessarily angiomatous.
*Candida albicans*
- While *Candida albicans* can cause various infections in immunocompromised individuals, including esophagitis and mucocutaneous candidiasis, it does not typically present with these specific bright red, friable vascular skin nodules.
- Disseminated candidiasis would more likely involve fungemia and widespread organ involvement, often with more subtle or different skin manifestations (e.g., maculopapular rash).
Dermal tumors and proliferations US Medical PG Question 8: A 52-year-old man presents to the office for evaluation of a 'weird rash' that appeared over his torso last week. The patient states that the rash just seemed to appear, but denies itching, pain, or exposure. On physical examination, the patient has multiple light brown-colored flat plaques on the torso. They appear to be 'stuck on' but do not have associated erythema or swelling. What condition is this clinical presentation most likely associated with?
- A. Gastric adenocarcinoma (Correct Answer)
- B. Slow-growing squamous cell carcinoma
- C. Insulin insensitivity
- D. Basal cell carcinoma (BCC)
- E. Infection with a Poxvirus
Dermal tumors and proliferations Explanation: ***Gastric adenocarcinoma***
- The description of a "weird rash" with multiple, **light brown-colored**, **flat plaques** that appear "stuck on" but lack erythema or swelling, appearing suddenly on the torso of a 52-year-old man, is highly suggestive of **leser-trélat sign**.
- **Leser-trélat sign** is a paraneoplastic syndrome characterized by the sudden eruption of multiple seborrheic keratoses, often associated with an underlying internal malignancy, most commonly **gastric adenocarcinoma**.
*Slow-growing squamous cell carcinoma*
- **Squamous cell carcinoma** typically presents as a scaly papule or nodule, often with ulceration or crusting, and is not characterized by widespread, flat, "stuck-on" lesions.
- While it is a malignancy, it does not typically manifest with the widespread eruption of seborrheic keratoses described by the Leser-Trélat sign.
*Insulin insensitivity*
- **Insulin insensitivity** can be associated with **acanthosis nigricans**, which presents as velvety, hyperpigmented plaques, particularly in skin folds.
- However, acanthosis nigricans lesions are distinct from the "stuck-on" appearance of seborrheic keratoses seen in Leser-Trélat sign and are not typically flat or light brown like in this case.
*Basal cell carcinoma (BCC)*
- **Basal cell carcinoma** usually presents as a **pearly nodule** with telangiectasias, often on sun-exposed areas.
- It does not cause a sudden eruption of multiple, flat, "stuck-on" plaques across the torso.
*Infection with a Poxvirus*
- **Poxvirus infections**, such as **molluscum contagiosum**, typically cause small, firm, umbilicated papules.
- These lesions are distinct from the flat, light brown plaques seen in this patient and are usually associated with a different clinical presentation.
Dermal tumors and proliferations US Medical PG Question 9: Two weeks after undergoing low anterior resection for rectal cancer, a 52-year-old man comes to the physician because of swelling in both feet. He has not had any fever, chills, or shortness of breath. His temperature is 36°C (96.8°F) and pulse is 88/min. Physical examination shows a normal thyroid and no jugular venous distention. Examination of the lower extremities shows bilateral non-pitting edema that extends from the feet to the lower thigh, with deep flexion creases. His skin is warm and dry, and there is no erythema or rash. Microscopic examination of the interstitial space in this patient's lower extremities would be most likely to show the presence of which of the following?
- A. Neutrophilic, protein-rich fluid
- B. Lymphocytic, hemosiderin-rich fluid
- C. Lipid-rich, protein-rich fluid (Correct Answer)
- D. Protein-rich, glycosaminoglycan-rich fluid
- E. Acellular, protein-poor fluid
Dermal tumors and proliferations Explanation: ***Lipid-rich, protein-rich fluid***
- The presentation of bilateral non-pitting edema extending to the thigh, with deep flexion creases, in a patient post-**low anterior resection** for rectal cancer, strongly suggests **lymphedema**.
- Lymphedema results from impaired lymphatic drainage, leading to the accumulation of **protein-rich fluid**, **macromolecules**, and **adipose tissue** in the interstitial space, which eventually becomes lipid-rich due to chronic inflammation and fibroblasts stimulating adipogenesis.
*Neutrophilic, protein-rich fluid*
- This description is characteristic of **inflammatory edema** or **purulent exudate**, typically seen in infections.
- The patient's lack of fever, chills, erythema, or warmth makes an infectious or acute inflammatory process unlikely.
*Lymphocytic, hemosiderin-rich fluid*
- **Hemosiderin deposits** are indicative of chronic **venous insufficiency** or recurrent hemorrhages, leading to red blood cell extravasation and breakdown.
- While lymphocytes can be present in chronic inflammation, the primary issue here is lymphatic obstruction, not venous stasis or bleeding.
*Protein-rich, glycosaminoglycan-rich fluid*
- While lymphedema is indeed **protein-rich**, the primary accumulation in mature lymphedema involves **adipose tissue** and fibrosis.
- **Glycosaminoglycans** accumulate significantly in conditions like **myxedema** (hypothyroidism), which was ruled out by the normal thyroid examination.
*Acellular, protein-poor fluid*
- This describes a **transudate**, typically seen in conditions like **heart failure**, **liver cirrhosis**, or **nephrotic syndrome** where there's an imbalance of hydrostatic and oncotic pressures.
- The edema in this case is **non-pitting**, suggesting a higher protein content and tissue changes characteristic of lymphatic dysfunction, not systemic fluid overload leading to protein-poor fluid.
Dermal tumors and proliferations US Medical PG Question 10: A 24-year-old man comes to the physician because of 2 episodes of bleeding from the rectum over the past month. The patient’s father died of colon cancer at the age of 42. The patient has no history of any serious illness and takes no medications. He does not smoke. His vital signs are within normal limits. Physical examination shows a small hard mass over the right mandible that is nontender and fixed to the underlying bone. A similarly hard and painless 5 × 5 mass is palpated over the rectus abdominis muscle. On examination of the rectum, a polypoid mass is palpated at fingertip. Proctosigmoidoscopy shows numerous polyps. Which of the following best explains these findings?
- A. Familial polyposis of the colon
- B. Peutz-Jeghers syndrome
- C. Turcot’s syndrome
- D. Gardner’s syndrome (Correct Answer)
- E. Lynch’s syndrome
Dermal tumors and proliferations Explanation: ***Gardner's syndrome***
- This syndrome is a variant of **familial adenomatous polyposis (FAP)**, characterized by numerous **colonic polyps** (leading to rectal bleeding) in conjunction with **extra-intestinal manifestations**.
- The extra-intestinal features described, such as **osteomas** (small hard mass over the mandible) and **desmoid tumors** (painless 5 × 5 mass over the rectus abdominis muscle), are classic findings of Gardner's syndrome. The family history of colon cancer further supports this diagnosis.
*Familial polyposis of the colon*
- Familial adenomatous polyposis (FAP) primarily involves the development of **hundreds to thousands of adenomatous colonic polyps**, leading to a high risk of colorectal cancer.
- While it explains the rectal polyps and family history, it does **not account for the extra-intestinal manifestations** like osteomas and desmoid tumors, which are key to Gardner's syndrome.
*Peutz-Jeghers syndrome*
- This syndrome is characterized by **hamartomatous polyps** throughout the gastrointestinal tract and **mucocutaneous hyperpigmentation** (dark spots) on the lips, buccal mucosa, and digits.
- The patient's presentation does not include hamartomatous polyps or mucocutaneous pigmentation.
*Turcot's syndrome*
- Turcot's syndrome is a rare condition involving the co-occurrence of **colorectal polyps** (often adenomatous) and **central nervous system (CNS) tumors**, such as medulloblastoma or glioblastoma.
- The patient presents with osteomas and desmoid tumors, which are not CNS manifestations central to Turcot's syndrome.
*Lynch's syndrome*
- Lynch syndrome (hereditary nonpolyposis colorectal cancer, HNPCC) is characterized by an increased risk of developing **colorectal cancer** and other cancers (e.g., endometrial, ovarian) due to defects in **DNA mismatch repair genes**.
- It typically involves fewer polyps than FAP and does not present with the specific extra-intestinal symptoms like osteomas or desmoid tumors seen in this patient.
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