Non-melanoma skin cancers US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Non-melanoma skin cancers. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Non-melanoma skin cancers US Medical PG Question 1: A 72-year-old man presents to the clinic for the evaluation of a lesion on his nose that has been slowly getting larger for the past 2 months. The patient notes no history of trauma, pruritus, or pain, but states that the size of the lesion is making his nose feel uncomfortable. On exam, the nodule is pink with rolled borders. Telangiectasias are also present within the lesion, with central ulceration. What is the characteristic histologic appearance of this lesion?
- A. Palisading nuclei (Correct Answer)
- B. Keratin pearls
- C. Sawtooth lymphocytic infiltrate
- D. Epidermal hyperplasia with cutaneous darkening
- E. Atypical melanocytes
Non-melanoma skin cancers Explanation: ***Palisading nuclei***
- The clinical presentation of a **slowly enlarging, pink nodule with rolled borders**, **telangiectasias**, and **central ulceration** on the nose is highly suggestive of **basal cell carcinoma (BCC)**.
- Histologically, BCC is characterized by nests of **basaloid cells** with **palisading nuclei** at the periphery of the tumor nests.
*Keratin pearls*
- **Keratin pearls**, or **dyskeratosis**, are characteristic histologic features of **squamous cell carcinoma (SCC)**, which typically presents with a more scaly or ulcerating lesion, often firmer and redder.
- While SCC can ulcerate, the **rolled borders** and **telangiectasias** are less common than in BCC.
*Sawtooth lymphocytic infiltrate*
- A **sawtooth lymphocytic infiltrate** at the dermo-epidermal junction is a classic histological finding in **lichen planus**, a pruritic, papular rash.
- This condition does not match the description of a solitary, enlarging nodule on the nose.
*Epidermal hyperplasia with cutaneous darkening*
- **Epidermal hyperplasia with cutaneous darkening** (acanthosis nigricans) is a velvety, hyperpigmented thickening of the skin, often associated with insulin resistance or malignancy.
- This is a diffuse skin change and does not resemble the localized, nodular lesion described.
*Atypical melanocytes*
- The presence of **atypical melanocytes** in the epidermis and/or dermis is characteristic of **melanoma** or precursor lesions like dysplastic nevi.
- Melanoma lesions typically show irregular borders, varied pigmentation, and rapid growth, which differ from the described lesion.
Non-melanoma skin cancers US Medical PG Question 2: A 34-year-old man presents to the office for evaluation of a lesion on his upper arm that appeared a few months ago and has not healed. The patient appears healthful but has a history of cardiovascular disease. He states that his friend at the industrial ammunition factory where he works told him he should "get it looked at." The patient admits to some nausea, vomiting, and diarrhea over the past year, but he states that he "feels fine now." On physical examination, the lesion is an erythematous, scaly, ulcerated plaque on the flexor surface of his upper arm. The rest of the exam is within normal limits. What is the most likely diagnosis?
- A. Squamous cell carcinoma (SCC) (Correct Answer)
- B. Erythema multiforme
- C. Actinic keratosis
- D. Erysipelas
- E. Contact dermatitis
Non-melanoma skin cancers Explanation: ***Squamous cell carcinoma (SCC)***
- The patient's occupational exposure to chemicals at an **ammunition factory**, along with chronic non-healing, **ulcerated, scaly plaque**, raises suspicion for SCC, particularly **arsenic-induced SCC**.
- His history of vague **gastrointestinal symptoms** (nausea, vomiting, diarrhea) over the past year is also consistent with **chronic arsenic exposure**, which is a known carcinogen.
*Erythema multiforme*
- This is an **acute, self-limiting hypersensitivity reaction** to medications or infections, characterized by target lesions, not a chronic, non-healing ulcerated plaque.
- It would not typically present with a history of chronic GI symptoms related to occupational exposure.
*Actinic keratosis*
- This is a **precancerous lesion** caused by chronic sun exposure, typically presenting as a rough, scaly patch on sun-exposed areas.
- While it has malignant potential to transform into SCC, the description of an **ulcerated, non-healing lesion** with a history of probable chemical exposure makes SCC a more likely *current* diagnosis.
*Erysipelas*
- Erysipelas is a **superficial bacterial infection** of the skin characterized by a rapidly spreading, bright red, well-demarcated, and painful rash, often accompanied by fever and systemic symptoms.
- It would not manifest as a chronic, non-healing ulcerated plaque over several months.
*Contact dermatitis*
- This is an **inflammatory skin reaction** due to direct contact with an allergen or irritant, typically presenting as an itchy, erythematous rash with vesicles or papules.
- It would not typically result in a chronic, ulcerated, non-healing plaque and is not associated with the systemic symptoms or occupational exposure history presented.
Non-melanoma skin cancers US Medical PG Question 3: A 61-year-old Caucasian male presents to your office complaining of morning headaches of 6 weeks duration. A head MRI reveals a likely metastasis of unknown origin in the supratentorial region of the brain. On biopsy, the neoplastic mass is shown to have a mutation in BRAF, a protein kinase, in which a glutamic acid is substituted for valine at position 600 of the protein. Where did this metastasis most likely originate?
- A. Stomach
- B. Skin (Correct Answer)
- C. Breast
- D. Brain
- E. Bone
Non-melanoma skin cancers Explanation: ***Skin***
- A brain metastasis with a **V600E BRAF mutation** is highly suggestive of **melanoma**, a type of skin cancer.
- Melanoma frequently metastasizes to the **brain**, and the BRAF V600E mutation is a common and actionable target in advanced melanoma.
*Stomach*
- Stomach cancers (gastric adenocarcinomas) less commonly metastasize to the brain compared to melanoma.
- While BRAF mutations can occur in gastric cancer, the **V600E mutation** is not typically a defining feature of gastric cancer metastases to the brain.
*Breast*
- Breast cancer can metastasize to the brain, but the presence of a **BRAF V600E mutation** is not a characteristic genetic alteration for breast cancer.
- Common mutations in breast cancer include those in **ER, PR, and HER2** receptors or **PIK3CA**, not BRAF V600E.
*Brain*
- The question states the mass is a **metastasis of unknown origin**, implying it did not originate in the brain itself.
- Primary brain tumors like **gliomas** would not be described as metastases and have a different mutational spectrum.
*Bone*
- Bone cancers (sarcomas) or metastases to the bone usually do not present with a **BRAF V600E mutation** as their primary driver for brain metastasis.
- While various cancers can metastasize to bone, the specific mutation points away from a bone origin.
Non-melanoma skin cancers US Medical PG Question 4: A 72-year-old man comes to the physician because of a lesion on his eyelid for 6 months. The lesion is not painful or pruritic. He initially dismissed it as a 'skin tag' but the lesion has increased in size over the past 3 months. He has type 2 diabetes mellitus, coronary artery disease, and left hemiplegia from a stroke 3 years ago. Current medications include sitagliptin, metformin, aspirin, and simvastatin. He used to work as a construction contractor and retired 3 years ago. Examination shows a 1-cm (0.4-in) flesh-colored, nodular, nontender lesion with rolled borders. There is no lymphadenopathy. Cardiopulmonary examination shows no abnormalities. Muscle strength is reduced in the left upper and lower extremities. Visual acuity is 20/20. The pupils are equal and reactive to light. A shave biopsy confirms the diagnosis of basal cell carcinoma. Which of the following is the most appropriate next step in management?
- A. Laser ablation
- B. Cryotherapy
- C. Topical chemotherapy
- D. Wide local excision
- E. Mohs micrographic surgery (Correct Answer)
Non-melanoma skin cancers Explanation: ***Mohs micrographic surgery***
- The lesion's location on the **eyelid** (a cosmetically and functionally sensitive area), its **nodular appearance** with **rolled borders**, and the likely diagnosis of **basal cell carcinoma (BCC)** make Mohs surgery the most appropriate treatment.
- Mohs surgery offers the highest cure rates for BCCs and preserves the maximum amount of healthy tissue, which is crucial for lesions on the face and eyelids.
*Wide local excision*
- While effective for many skin cancers, **wide local excision** might lead to significant cosmetic or functional defects on the eyelid due to the need for a wider margin of healthy tissue removal.
- Its cure rates are generally lower than Mohs surgery for high-risk BCCs, especially in sensitive areas.
*Laser ablation*
- **Laser ablation** is typically used for superficial or precancerous lesions, not for nodular, invasive basal cell carcinoma.
- It does not allow for histological margin control, which is essential to ensure complete tumor removal and reduce recurrence.
*Cryotherapy*
- **Cryotherapy** is suitable for small, superficial, or pre-malignant lesions, but not for a nodular lesion on the eyelid where tissue preservation and precise margin control are critical.
- It does not offer histological confirmation of clear margins, increasing the risk of recurrence.
*Topical chemotherapy*
- **Topical chemotherapy** (e.g., imiquimod, 5-fluorouracil) is generally reserved for superficial basal cell carcinomas distant from critical structures.
- It is not effective for nodular BCCs and lacks the ability to confirm complete tumor removal via microscopic margin assessment.
Non-melanoma skin cancers US Medical PG Question 5: A 62-year-old woman comes to the physician for evaluation of a mole on her forearm that has increased in size over the last several months. Physical examination shows a 9-mm skin lesion on the right forearm with irregular borders. An excisional biopsy is performed, and genetic analysis shows a mutation in the gene that encodes B-Raf. Which of the following cellular events most likely predisposed this patient to developing this skin lesion?
- A. Deamination of cytosine, guanine, and adenine nucleotides
- B. Relocation of a chromosomal segment onto a nonhomologous chromosome
- C. Formation of covalent bonds between adjacent pyrimidine bases (Correct Answer)
- D. Insufficient phosphorylation of p53
- E. Double-strand breaks in DNA molecules
Non-melanoma skin cancers Explanation: ***Formation of covalent bonds between adjacent pyrimidine bases***
- This describes **pyrimidine dimers**, typically **thymine dimers**, which are formed due to **UV radiation exposure**.
- UV radiation is the primary environmental risk factor for **melanoma**, and the **B-Raf mutation** (common in melanoma) is often linked to these UV-induced DNA lesions.
*Deamination of cytosine, guanine, and adenine nucleotides*
- **Deamination** is a chemical alteration of DNA bases that can lead to mutations, but it is not the most direct or common mechanism for UV-induced melanoma.
- While deamination can occur spontaneously or be induced by certain chemicals, it is not the primary event linked to **UV radiation** and **B-Raf mutations** in melanoma.
*Relocation of a chromosomal segment onto a nonhomologous chromosome*
- This describes a **translocation**, a type of chromosomal rearrangement.
- While translocations can be associated with some cancers (e.g., leukemias, sarcomas), they are not the typical mechanism for initiating **melanoma** or directly causing **B-Raf mutations**.
*Insufficient phosphorylation of p53*
- **p53 phosphorylation** is crucial for its activation as a tumor suppressor protein, and insufficient phosphorylation would impair its function.
- However, the direct cause of this specific melanoma with a **B-Raf mutation** is usually DNA damage (like pyrimidine dimers) rather than a primary defect in p53 phosphorylation.
*Double-strand breaks in DNA molecules*
- **Double-strand breaks (DSBs)** are highly deleterious DNA lesions that can lead to chromosomal rearrangements or cell death if not repaired.
- While DSBs can be caused by various factors, including high-energy radiation, they are not the most common or characteristic DNA lesion specifically implicated in the initiation of **melanoma** due to UV exposure and subsequent **B-Raf mutation**.
Non-melanoma skin cancers US Medical PG Question 6: A 38-year-old woman applies a PABA sunscreen to her skin before going to the beach. Which type(s) of ultraviolet light will it protect her against?
- A. UVA and UVB
- B. UVB and UVC
- C. UVB (Correct Answer)
- D. UVA
- E. UVC
Non-melanoma skin cancers Explanation: ***UVB***
- **Para-aminobenzoic acid (PABA)** and its derivatives primarily absorb **UVB radiation** (290-320 nm), which is responsible for sunburn and erythema.
- PABA-containing sunscreens are effective at preventing the acute effects of sun exposure like sunburn caused by UVB.
- Traditional PABA sunscreens are primarily effective against **UVB only**, not broad-spectrum.
*UVA and UVB*
- While some modern sunscreens offer broad-spectrum protection against both UVA and UVB, traditional PABA sunscreens are primarily effective against **UVB only**.
- **UVA filters** (e.g., avobenzone, zinc oxide, titanium dioxide) are needed in addition to PABA to achieve protection against both types of radiation.
*UVB and UVC*
- PABA sunscreens protect against **UVB**, but **UVC radiation** (100-280 nm) is mostly blocked by the Earth's ozone layer and does not reach the Earth's surface.
- Sunscreens are not typically formulated to protect against UVC, as it is not a clinical concern for typical sun exposure.
*UVA*
- PABA is **not effective** at significantly absorbing or blocking **UVA radiation** (320-400 nm), which is primarily associated with photoaging, deeper skin damage, and tanning.
- Protection against UVA requires different chemical filters (avobenzone, ecamsule) or physical blockers (zinc oxide, titanium dioxide).
*UVC*
- **UVC radiation** does not reach the Earth's surface due to complete absorption by the ozone layer, making protection against it unnecessary for sunscreen formulations.
- Sunscreens, including those containing PABA, are not designed to filter UVC as it poses no risk in normal outdoor settings.
Non-melanoma skin cancers US Medical PG Question 7: A 49-year-old woman presents to her physician with complaints of breast swelling and redness of the skin over her right breast for the past 1 month. She also mentions that the skin above her right breast appears to have thickened. She denies any pain or nipple discharge. The past medical history is significant for a total abdominal hysterectomy at 45 years of age. Her last mammogram 1 year ago was negative for any pathologic changes. On examination, the right breast was diffusely erythematous with gross edema and tenderness and appeared larger than the left breast. The right nipple was retracted and the right breast was warmer than the left breast. No localized mass was palpated. Which of the following statements best describes the patient’s most likely condition?
- A. It shows predominant lymphatic spread.
- B. The lesion expresses receptors for estrogen and progesterone.
- C. The lesion is due to Streptococcal infection.
- D. It is a benign lesion.
- E. The inflammation is due to obstruction of dermal lymphatic vessels. (Correct Answer)
Non-melanoma skin cancers Explanation: ***The inflammation is due to obstruction of dermal lymphatic vessels.***
- The presentation of **rapid-onset breast swelling, redness, thickening of the skin, warmth, and nipple retraction** without a palpable mass is highly suggestive of **inflammatory breast cancer (IBC)**.
- IBC is characterized by the **obstruction of dermal lymphatic vessels by tumor cells**, leading to the classic inflammatory signs and **peau d'orange** appearance.
*It shows predominant lymphatic spread.*
- While IBC does involve **lymphatic spread**, this statement alone does not fully encompass the characteristic pathology of the condition causing the observed symptoms.
- The obstruction of the **dermal lymphatic vessels** is a more precise description of the immediate cause of the clinical presentation.
*The lesion expresses receptors for estrogen and progesterone.*
- Although some breast cancers are **hormone receptor-positive (ER/PR positive)**, there is no direct information in the vignette to suggest this specificity for the patient's condition.
- This statement refers to a **molecular characteristic** that is not a defining feature of the clinical presentation of IBC.
*The lesion is due to Streptococcal infection.*
- While a **bacterial infection** (like **streptococcal cellulitis**) can cause redness, swelling, and warmth, it typically presents with more acute symptoms, fever, and often a clearer response to antibiotics.
- The **thickening of the skin** and **nipple retraction** point away from a simple infection and towards a malignant process.
*It is a benign lesion.*
- The rapid progression of symptoms, pronounced skin changes, and nipple retraction are all **red flags for malignancy**, specifically inflammatory breast cancer.
- **Benign lesions** rarely cause such diffuse, severe, and rapidly progressing inflammatory signs.
Non-melanoma skin cancers US Medical PG Question 8: A 12-year-old boy is brought to the emergency department after he vomited and said he was having double vision in school. He also says that he has been experiencing morning headaches, nausea, and dizziness over the last month. He has no past medical history and is not taking any medications. Physical exam reveals a broad-based gait, dysmetria on finger-to-nose testing, and nystagmus. Both serum and urine toxicology are negative, and radiography reveals a solid mass in the midline cerebellum that enhances after contrast administration. Biopsy of this lesion reveals cells of primitive neuroectodermal origin. Which of the following would most likely be seen on histology of this lesion?
- A. Rosettes with small blue cells (Correct Answer)
- B. Rosenthal fibers
- C. Tooth enamel-like calcification
- D. Foamy cells and high vascularity
- E. Perivascular pseudorosettes
Non-melanoma skin cancers Explanation: ***Rosettes with small blue cells***
- The description of a **midline cerebellar mass** in a child, presenting with signs of **increased intracranial pressure (headaches, vomiting, double vision)** and **cerebellar dysfunction (broad-based gait, dysmetria, nystagmus)**, is classic for **medulloblastoma**.
- **Medulloblastomas** are primitive neuroectodermal tumors (PNETs) known for their distinctive histology of **small, round, blue cells** forming **Homer-Wright rosettes**.
*Rosenthal fibers*
- **Rosenthal fibers** are eosinophilic, corkscrew-shaped structures that are characteristic histological features of **pilocytic astrocytomas**.
- While pilocytic astrocytomas can be cerebellar and common in children, the question describes a "solid mass of primitive neuroectodermal origin" rather than the typical cystic lesion with mural nodule associated with pilocytic astrocytomas, and the aggressive presentation points away from pilocytic astrocytoma.
*Tooth enamel-like calcification*
- **Tooth enamel-like calcification** is a pathognomonic feature of **craniopharyngiomas**, which are typically supratentorial (in the sellar region) and cause symptoms related to pituitary dysfunction and optic chiasm compression, not cerebellar dysfunction.
- The location and symptoms provided in the vignette do not match the typical presentation of a craniopharyngioma.
*Foamy cells and high vascularity*
- **Foamy cells and high vascularity** are characteristic features of **hemangioblastomas**, which are typically seen in adults, often associated with **von Hippel-Lindau disease**, and are more commonly located in the cerebellum.
- However, the patient's age (12-year-old) and the description of cells of "primitive neuroectodermal origin" do not align with the typical presentation or origin of hemangioblastomas.
*Perivascular pseudorosettes*
- **Perivascular pseudorosettes** are the classic histological finding in **ependymomas**, another common pediatric brain tumor.
- While ependymomas can occur in the posterior fossa, they typically arise from the floor of the fourth ventricle and are not described as having primitive neuroectodermal origin in the same way medulloblastomas are, and the specific rosettes formed by medulloblastomas are Homer-Wright rosettes.
Non-melanoma skin cancers US Medical PG Question 9: A 50-year-old woman with rheumatoid arthritis on methotrexate develops rapidly progressive painful ulcers on her legs with violaceous undermined borders. Biopsy shows neutrophilic dermal infiltrate with areas of necrosis, but no vasculitis or infection. Wound cultures are negative. Despite debridement, the ulcers worsen. C-ANCA and P-ANCA are negative. Evaluate the diagnosis and determine the management that addresses both the cutaneous condition and systemic disease.
- A. Discontinue all immunosuppression to allow wound healing
- B. Increase methotrexate dose and add wound care
- C. Discontinue methotrexate, start cyclosporine and prednisone
- D. Start broad-spectrum antibiotics and surgical debridement
- E. Continue methotrexate, add TNF-alpha inhibitor and systemic corticosteroids (Correct Answer)
Non-melanoma skin cancers Explanation: ***Continue methotrexate, add TNF-alpha inhibitor and systemic corticosteroids***
- This patient presents with **Pyoderma Gangrenosum (PG)**, a neutrophilic dermatosis characterized by **violaceous undermined borders** and **pathergy**, where surgical debridement cause lesion expansion.
- **TNF-alpha inhibitors** (e.g., adalimumab, infliximab) are first-line for recalcitrant PG and simultaneously provide excellent control for the underlying **Rheumatoid Arthritis**.
*Discontinue all immunosuppression to allow wound healing*
- Since PG is an **autoimmune inflammatory condition**, withdrawing immunosuppression would result in rapid progression of the ulcers rather than healing.
- Wound healing in PG requires **suppressing the inflammatory response** rather than the typical wound care approach for infected ulcers.
*Increase methotrexate dose and add wound care*
- While **methotrexate** treats RA, it is often insufficient as a monotherapy for the acute, rapidly progressive phase of **Pyoderma Gangrenosum**.
- Standard wound care alone is ineffective because the primary driver is **neutrophilic infilatration**, which requires targeted biologic or corticosteroid therapy.
*Discontinue methotrexate, start cyclosporine and prednisone*
- While **cyclosporine** and **prednisone** are used for PG, discontinuing methotrexate may lead to a flare of the patient’s **Rheumatoid Arthritis**.
- Maintaining a coordinated regimen that addresses both the skin and the joints, such as adding a **TNF-alpha inhibitor**, is preferred over switching all medications.
*Start broad-spectrum antibiotics and surgical debridement*
- **Surgical debridement** is contraindicated in PG due to **pathergy**, a phenomenon where trauma to the skin induces new or worsening lesions.
- **Antibiotics** are unnecessary as the biopsy and cultures confirmed a **sterile neutrophilic infiltrate** rather than an infectious process.
Non-melanoma skin cancers US Medical PG Question 10: A 25-year-old woman presents with painful oral ulcers and a pustular rash at venipuncture sites. She has genital ulcers and a history of recurrent uveitis. Skin biopsy from a pustule shows neutrophilic infiltrate in the dermis without vasculitis or infection. HLA-B51 testing is positive. She is planning pregnancy. Evaluate the management strategy considering disease control and pregnancy planning.
- A. Start methotrexate for disease control
- B. Start colchicine monotherapy and proceed with pregnancy
- C. Start high-dose corticosteroids and azathioprine, delay pregnancy
- D. Start infliximab, use contraception, then transition to low-risk therapy before conception (Correct Answer)
- E. Avoid all immunosuppression and manage symptoms only
Non-melanoma skin cancers Explanation: ***Start infliximab, use contraception, then transition to low-risk therapy before conception***
- This patient has **Beh'et's disease** with **recurrent uveitis**, which is **sight-threatening** and requires aggressive biological therapy like **infliximab** or **TNF-inhibitors** for rapid remission.
- Achievng **remission** before pregnancy is vital; while TNF-inhibitors are often continued, transitioning to pregnancy-compatible agents like **azathioprine** or **colchicine** ensures long-term safety.
*Start methotrexate for disease control*
- **Methotrexate** is strictly **teratogenic** and must be avoided in patients planning pregnancy or discontinued months before conception.
- While it can treat some aspects of systemic inflammation, it is not the first-line gold standard for **acute ocular Beh'et's** compared to biologics.
*Start colchicine monotherapy and proceed with pregnancy*
- **Colchicine** is excellent for **mucocutaneous** symptoms (oral and genital ulcers) but is insufficient as monotherapy to prevent blindness from **recurrent uveitis**.
- Relying on monotherapy in a patient with active ocular disease risks **permanent vision loss** during the pregnancy period.
*Start high-dose corticosteroids and azathioprine, delay pregnancy*
- While **azathioprine** is used for maintenance, **high-dose corticosteroids** carry significant side effects and are usually a bridge, not a comprehensive plan for ocular stabilization.
- This strategy lacks the rapid, potent **TNF-alpha inhibition** needed to quickly arrest the neutrophilic inflammation seen in severe Beh'et's flare-ups.
*Avoid all immunosuppression and manage symptoms only*
- **Beh'et's disease** is a multi-system inflammatory disorder; leaving **uveitis** and systemic vasculitis untreated leads to irreversible organ damage and **blindness**.
- Symptomatic management alone ignores the **neutrophilic infiltrate** and underlying autoimmune process, which could also lead to pregnancy complications due to active maternal disease.
More Non-melanoma skin cancers US Medical PG questions available in the OnCourse app. Practice MCQs, flashcards, and get detailed explanations.
