Bone and Soft Tissue Pathology Practice Questions

Q: Histology of a biopsy from a long bone is shown below. Which of the following is the likely diagnosis?

Paget's disease. ***Paget's disease*** - Characterized by a distinctive **mosaic cement line pattern** with irregular, thick trabeculae showing alternating areas of bone formation and resorption. - Shows increased **osteoclast and osteoblast activity** with enlarged, multinucleated osteoclasts and prominent osteoblasts lining bone surfaces. *Osteoporosis* - Shows **thinned trabeculae** with normal bone architecture and reduced bone mass, not the thickened irregular pattern seen here. - Lacks the characteristic **mosaic cement lines** and increased cellular activity typical of Paget's disease. *Osteosclerosis* - Presents with **increased bone density** and thickened trabeculae but maintains normal lamellar bone structure. - Does not show the **irregular mosaic pattern** or the chaotic bone remodeling seen in Paget's disease. *Osteomalacia* - Characterized by **excess unmineralized osteoid** appearing as pink, amorphous material around bone trabeculae. - Shows **wide osteoid seams** and delayed mineralization, unlike the mixed sclerotic and lytic pattern of Paget's disease.

Q: What is the gene responsible for Van der Woude syndrome?

IRF6. **Explanation:** **Van der Woude Syndrome (VWS)** is an autosomal dominant condition characterized by the combination of paramedian lower lip pits, cleft lip, and/or cleft palate. It is the most common form of syndromic orofacial clefting. 1. **Why IRF6 is correct:** The syndrome is caused by mutations in the **Interferon Regulatory Factor 6 (IRF6)** gene located on chromosome 1. IRF6 plays a critical role in the formation of connective tissue and the development of the craniofacial structure, specifically the fusion of the palate and the formation of the skin and oral mucosa. 2. **Why the other options are incorrect:** * **FGFR2 (Fibroblast Growth Factor Receptor 2):** Mutations in this gene are associated with craniosynostosis syndromes such as **Apert, Crouzon, and Pfeiffer syndromes**, characterized by premature fusion of skull bones. * **HGHF2:** This is associated with **Hereditary Gingival Fibromatosis**, a rare condition causing benign overgrowth of the gingival tissues. * **GAT02:** This is not a recognized gene associated with major craniofacial or bone pathologies relevant to the NEET-PG curriculum. **Clinical Pearls for NEET-PG:** * **Most Common Feature:** Paramedian lower lip pits (seen in 88% of cases). * **Genetics:** Autosomal Dominant with high penetrance but variable expressivity. * **Popliteal Pterygium Syndrome (PPS):** Also caused by mutations in the **IRF6** gene (allelic to VWS), but presents with additional features like skin webs (pterygia) and genitourinary anomalies. * **High-Yield Association:** If a question mentions "lip pits + cleft palate," always look for IRF6.

Question 1

Which of the following is NOT associated with Paget's disease of bone?

Accepted Answer

Malignant transformation in less than 1% of cases

Answer

Virus association

Answer

Progression to chondrosarcoma

Answer

Osteosclerotic phase is seen

Question 2

Which of the following statements regarding glomus tumors is not true?

Accepted Answer

It is usually asymptomatic and produces pain only if it undergoes malignant change.

Answer

It is a benign tumor of the glomus body.

Answer

The most common site is the distal phalanges.

Answer

It is a tumor of modified smooth muscle cells.

Question 3

A 50-year-old woman presents with a painless soft tissue mass in her right thigh. Upon surgical excision, the surgeon notices that the tumor is adherent to the surrounding tissues. Histologic analysis reveals a neoplasm composed of pleomorphic clear cells, with vacuolated cytoplasm. The nucleus of many cells is indented by the cytoplasmic vacuoles, which are stained by histochemical methods for lipids. Which of the following is the most likely diagnosis?

Accepted Answer

Liposarcoma

Answer

Chondrosarcoma

Answer

Lipoma

Answer

Metastatic adenocarcinoma

Question 4

Decreased mineralization of the epiphyseal plate in a growing child is seen in which condition?

Accepted Answer

Rickets

Answer

Osteomalacia

Answer

Scurvy

Answer

Osteoporosis

Question 5

A 25-year-old male patient presents with a bony expansile swelling of the right body of the mandible and mild paresthesia of the right inferior dental nerve. OPG shows a multilocular radiolucency without root resorption. What is odontogenic keratocyst noted for?

Accepted Answer

Daughter cysts and high rate of recurrence

Answer

Malignant transformation

Answer

Impacted teeth

Answer

Nodal metastasis

Question 6

Rickets is characterized by what?

Accepted Answer

All of the above

Answer

Decrease in Calcium content of bone

Answer

Widening of growth cartilage

Answer

Beading of ribs

Question 7

Histology of a biopsy from a long bone is shown below. Which of the following is the likely diagnosis?

Accepted Answer

Paget's disease

Answer

Osteoporosis

Answer

Osteosclerosis

Answer

Osteomalacia

Question 8

Which of the following are common primary sites of metastasis to the brain?

Accepted Answer

Thyroid carcinoma

Answer

Tongue carcinoma

Answer

Lung carcinoma

Answer

Breast carcinoma

Question 9

What is the gene responsible for Van der Woude syndrome?

Accepted Answer

IRF6

Answer

FGFR2

Answer

HGHF2

Answer

GAT02

Question 10

Bone dysplasia is invariably seen in which of the following?

Accepted Answer

Developmental defect

Answer

Hyperparathyroidism

Answer

Osteosarcoma

Answer

Osteomalacia

Bone and Soft Tissue Pathology — MCQs

Bone and Soft Tissue Pathology — MCQs

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