Bone and Soft Tissue Pathology Practice Questions

Q: Which of the following tumors most closely resembles a hemangiopericytoma?

Glomus tumor. The correct answer is **Glomus tumor**. The resemblance between a glomus tumor and a hemangiopericytoma lies in their **perivascular origin** [1]. A glomus tumor is a benign neoplasm arising from the modified smooth muscle cells of the **glomus body** (a specialized arteriovenous anastomosis involved in thermoregulation) [1]. Historically, hemangiopericytoma was defined by its "staghorn" vascular pattern and perivascular spindle cells [1]. While the term "hemangiopericytoma" is now largely replaced by the **Solitary Fibrous Tumor (SFT)** spectrum in modern pathology, the classic description emphasizes cells surrounding vascular spaces, a feature shared by the glomus tumor [1]. **Analysis of Incorrect Options:** * **A. Hemangioma:** This is a benign proliferation of blood vessels (capillary or cavernous) lined by endothelial cells, not perivascular cells [1]. * **C. Ewing’s Sarcoma:** A small round blue cell tumor characterized by the t(11;22) translocation. While it can be highly vascular, its cellular morphology does not mimic pericytes. * **D. Plasmacytoma:** A localized collection of neoplastic plasma cells (clock-face chromatin, perinuclear hof). It is a hematological malignancy unrelated to vascular pericytes. **NEET-PG High-Yield Pearls:** * **Glomus Tumor Triad:** Exquisite pain, localized tenderness, and sensitivity to cold. * **Common Site:** Subungual region (under the fingernails). * **Immunohistochemistry (IHC):** Glomus tumors are positive for **SMA (Smooth Muscle Actin)** and negative for endothelial markers like CD31/CD34 (unlike hemangiomas). * **Staghorn/Deer-horn vasculature:** This is the classic histological buzzword for Solitary Fibrous Tumor (formerly hemangiopericytoma). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 523-524.

Q: In Duchenne's muscular dystrophy, what is the state of the calf muscle?

Pseudohypertrophied. **Explanation:** In **Duchenne Muscular Dystrophy (DMD)**, the calf muscles (gastrocnemius and soleus) characteristically appear enlarged, a phenomenon known as **Pseudohypertrophy**. **Why Pseudohypertrophy is the correct answer:** DMD is an X-linked recessive disorder caused by a mutation in the **Dystrophin gene** (the largest known human gene) [1]. The absence of dystrophin leads to progressive myofiber necrosis. As muscle fibers are lost, they are replaced by an extensive proliferation of **fibro-fatty tissue** (fat and connective tissue). This replacement increases the bulk of the muscle, making it look "hypertrophied" to the naked eye, while the actual functional muscle tissue is severely diminished. **Analysis of Incorrect Options:** * **Hypertrophied:** True hypertrophy involves an increase in the size of individual muscle fibers (e.g., in athletes). In DMD, the muscle fibers are actually dying, not growing [1]. * **Atrophied:** While the muscle fibers themselves undergo atrophy and necrosis, the overall clinical appearance of the calf is one of enlargement due to fat deposition, making "atrophied" clinically inaccurate for the calf. * **Pseudoatrophied:** This is not a standard pathological term used to describe the clinical presentation of DMD. **NEET-PG High-Yield Pearls:** * **Gower’s Sign:** Patients use their hands to "climb up" their own legs to stand up due to proximal muscle weakness. * **Biochemical Marker:** Serum **Creatine Kinase (CK)** levels are massively elevated (often 10–100x normal) from birth. * **Becker Muscular Dystrophy:** A milder form where dystrophin is truncated/mutated but present (unlike DMD where it is absent) [1]. * **Cause of Death:** Usually respiratory failure or **Dilated Cardiomyopathy**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Peripheral Nerves and Skeletal Muscles, pp. 1244-1245.

Q: Calcification of the intervertebral disc is a feature of which condition?

Alkaptonuria. **Explanation:** **Alkaptonuria** is an autosomal recessive metabolic disorder caused by a deficiency of the enzyme **homogentisate 1,2-dioxygenase**. This leads to the accumulation of homogentisic acid (HGA) in the body. HGA binds to collagen in connective tissues, a process known as **Ochronosis**. In the spine, this pigment deposition leads to the degeneration, narrowing, and subsequent **calcification of the intervertebral discs**. On X-ray, this appears as "wafer-like" calcification of multiple discs, which is a classic diagnostic hallmark. **Analysis of Incorrect Options:** * **Ankylosing Spondylitis:** Characterized by "Bamboo spine" due to marginal syndesmophytes and fusion of the sacroiliac joints, but it does not typically feature primary disc calcification. * **Hyperparathyroidism:** Associated with "Rugger-jersey spine" (subperiosteal resorption and sclerosis) and metastatic calcification in soft tissues, but not specifically isolated intervertebral disc calcification. * **Charcot’s Disease (Neuropathic Joint):** Leads to severe joint destruction, disorganized bone formation (debris), and sclerosis due to loss of sensation, but not the systematic calcification of discs. **High-Yield NEET-PG Pearls:** * **Triad of Alkaptonuria:** 1. Homogentisic aciduria (urine turns black on standing/alkalinization), 2. Ochronosis (blue-black pigmentation of cartilage/sclera), 3. Ochronotic arthritis. * **Radiology:** Look for the "wafer-like" calcification of intervertebral discs and narrowing of the joint space. * **Diagnosis:** Confirmed by detecting homogentisic acid in urine using thin-layer chromatography or the Ferric Chloride test (transient green color).

Q: Cystosarcoma phylloides is a tumor of which organ?

Breast. **Explanation:** **Cystosarcoma Phyllodes** (or Phyllodes tumor) is a fibroepithelial neoplasm of the **Breast** [1]. It arises from the intralobular stroma and is characterized by a "leaf-like" (phyllodes) growth pattern of hypercellular stroma pushing into the overlying epithelium [1]. 1. **Why Breast is Correct:** Phyllodes tumors are distinct from common fibroadenomas due to their increased stromal cellularity, mitotic activity, and potential for malignancy [1], [2]. They typically present in women in their 40s and 50s as large, rapidly growing, painless masses. 2. **Why Other Options are Incorrect:** * **Liver:** Primary tumors include Hepatocellular Carcinoma or Hemangiomas; phyllodes-type morphology is not seen here. * **Colon:** Common tumors are Adenocarcinomas or GISTs. * **Uterus:** While the uterus has stromal tumors (e.g., Leiomyomas or Endometrial Stromal Sarcomas), Cystosarcoma Phyllodes is specific to the mammary gland. **High-Yield Clinical Pearls for NEET-PG:** * **Morphology:** Characterized by "leaf-like" cytoplasmic projections and increased stromal cellularity [1]. * **Grading:** They are classified as Benign, Borderline, or Malignant based on mitotic figures, stromal overgrowth, and nuclear atypia [1], [2]. * **Metastasis:** Unlike breast adenocarcinoma, malignant phyllodes tumors spread via the **hematogenous route** (most commonly to the lungs), not the lymphatics [1]. Axillary lymph node dissection is usually not required. * **Treatment:** Wide local excision with negative margins is the gold standard to prevent local recurrence [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, p. 1074. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 459-462.

Q: What is the most common soft tissue tumor in adults?

Malignant fibrous histiocytoma. **Malignant Fibrous Histiocytoma (MFH)**, now more accurately reclassified in modern WHO terminology as **Undifferentiated Pleomorphic Sarcoma (UPS)**, is historically and clinically recognized as the most common soft tissue sarcoma in adults, particularly in the 50–70 age group. It typically arises in the deep soft tissues of the extremities (especially the thigh) or the retroperitoneum. It is characterized histologically by a "storiform" or cartwheel growth pattern of spindle cells and significant cellular pleomorphism. **Analysis of Options:** * **A. Embryonal Rhabdomyosarcoma:** This is the most common soft tissue sarcoma in **children** (usually under age 10) [1], typically occurring in the head, neck, or genitourinary tract. * **B. Liposarcoma:** This is the second most common soft tissue sarcoma in adults [1]. While very frequent, it statistically follows UPS/MFH in overall incidence [1]. * **C. Synovial Sarcoma:** This is a common sarcoma in young adults (20–40 years) and is characterized by a unique t(X;18) translocation [1]. It is not the most common overall [1]. **High-Yield Pearls for NEET-PG:** * **Most common benign soft tissue tumor (Adults):** Lipoma [1]. * **Most common malignant soft tissue tumor (Adults):** Malignant Fibrous Histiocytoma (UPS). * **Most common soft tissue sarcoma (Children):** Rhabdomyosarcoma [1]. * **Most common site for MFH:** Lower extremity (Thigh). * **Key Histology:** Storiform pattern and marked nuclear atypia. * **Note on Nomenclature:** If "Undifferentiated Pleomorphic Sarcoma" appears in options instead of MFH, it is the preferred modern term. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1222-1226.

Question 1

Giant cell lesions of the periodontium are best considered as?

Accepted Answer

Non-neoplastic reactive lesions

Answer

Benign neoplasms

Answer

Malignant neoplasms

Answer

None of the above

Question 2

Which of the following tumors most closely resembles a hemangiopericytoma?

Accepted Answer

Glomus tumor

Answer

Hemangioma

Answer

Ewing's sarcoma

Answer

Plasmacytoma

Question 3

In Duchenne muscular dystrophy, the defect is in the gene producing which protein?

Accepted Answer

Dystrophin

Answer

Alpha-actinin

Answer

Nebulin

Answer

Desmin

Question 4

In Duchenne's muscular dystrophy, what is the state of the calf muscle?

Accepted Answer

Pseudohypertrophied

Answer

Hypertrophied

Answer

Atrophied

Answer

Pseudoatrophied

Question 5

Calcification of the intervertebral disc is a feature of which condition?

Accepted Answer

Alkaptonuria

Answer

Ankylosing spondylitis

Answer

Hyperparathyroidism

Answer

Charcot's disease

Question 6

Which of the following bone diseases characteristically exhibits a single lesion in a single bone?

Accepted Answer

Central giant cell granuloma

Answer

Osteopetrosis

Answer

Paget's disease of the bone

Answer

Polyostotic fibrous dysplasia

Question 7

Which of the following is TRUE about desmoid tumors?

Accepted Answer

Alterations in the Adenomatous Polyposis Coli (APC) / beta-catenin pathway are noted.

Answer

They consist of proliferating malignant-appearing fibroblastic cells with abundant mitoses.

Answer

Primary modality of treatment is radiotherapy.

Answer

They have a strong tendency to metastasize.

Question 8

Cystosarcoma phylloides is a tumor of which organ?

Accepted Answer

Breast

Answer

Liver

Answer

Colon

Answer

Uterus

Question 9

What is the most common soft tissue tumor in adults?

Accepted Answer

Malignant fibrous histiocytoma

Answer

Embryonal rhabdomyosarcoma

Answer

Liposarcoma

Answer

Synovial sarcoma

Question 10

What is the most common histological type of rhabdomyosarcoma?

Accepted Answer

Embryonal

Answer

Pleomorphic

Answer

Alveolar

Answer

Botryoid

Bone and Soft Tissue Pathology — MCQs

Bone and Soft Tissue Pathology — MCQs

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