Bone and Soft Tissue Pathology Practice Questions

Q: Marked reduction in the amount of dentin, widening of predentin layer, and presence of large areas of interglobular dentin are characteristic features of which condition?

Regional odontodysplasia. **Explanation:** **Regional Odontodysplasia (ROD)**, also known as **"Ghost Teeth,"** is a rare, non-hereditary developmental anomaly affecting the ectodermal and mesodermal tooth components. The characteristic histopathological features described—marked reduction in dentin volume, a widened predentin layer, and extensive areas of **interglobular dentin** (unfused calcification foci)—result from defective mineralization of the organic matrix. Radiographically, these teeth show thin enamel and dentin with enlarged pulp chambers, giving them a faint, "ghost-like" appearance. **Analysis of Incorrect Options:** * **Dentinogenesis Imperfecta:** This is a hereditary defect of dentin. While it shows thin dentin, the hallmark is the **obliteration of pulp chambers** due to continuous deposition of abnormal dentin, and it lacks the specific "ghostly" radiographic appearance of ROD. * **Amelogenesis Imperfecta:** This condition primarily affects the **enamel** (ectodermal origin). The dentin and pulp remain histologically and radiographically normal. * **Osteogenesis Imperfecta:** This is a systemic connective tissue disorder caused by Type I collagen mutations. While it is frequently associated with Dentinogenesis Imperfecta (Type I), it does not present with the localized, "regional" interglobular dentin patterns seen in ROD. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** ROD usually affects a localized quadrant (unilateral) and often involves both primary and permanent dentition. * **Radiographic Sign:** The "Ghost Teeth" appearance is the classic buzzword. * **Etiology:** Unlike the other options, ROD is **idiopathic and non-hereditary**, often attributed to local vascular or traumatic factors during tooth development.

Q: Fibrous dysplasia associated with intramuscular myxoma is known as:

Maza rahe syndrome. **Explanation:** **Mazabraud Syndrome** (often spelled phonetically in exams as Maza rahe syndrome) is a rare condition characterized by the association of **fibrous dysplasia** (usually polyostotic) and **intramuscular myxomas** [1]. Both lesions are linked to post-zygotic mutations in the **GNAS1 gene**, which leads to constitutive activation of the Gs-alpha protein. The myxomas typically appear years after the bone lesions and are most commonly found in the large muscles of the thigh [1]. **Analysis of Incorrect Options:** * **Hans-Schüller-Christian Disease:** This is a clinical triad of multifocal **Langerhans Cell Histiocytosis (LCH)** consisting of calvarial bone defects, exophthalmos, and diabetes insipidus. It is unrelated to fibrous dysplasia. * **Marfan Syndrome:** A connective tissue disorder caused by mutations in the **FBN1 gene** (fibrillin-1). It presents with skeletal abnormalities (arachnodactyly, pectus excavatum), ectopia lentis, and aortic root dilation. * **Ehlers-Danlos Syndrome:** A group of disorders affecting **collagen synthesis**, primarily characterized by joint hypermobility, skin hyperextensibility, and tissue fragility. **High-Yield Clinical Pearls for NEET-PG:** * **McCune-Albright Syndrome:** Another GNAS mutation-related disorder featuring polyostotic fibrous dysplasia, **Café-au-lait spots** (Coast of Maine borders), and **precocious puberty** (endocrinopathies) [1]. * **Radiology of Fibrous Dysplasia:** Classically described as having a **"Ground-glass appearance"** on X-ray. * **Histology:** Characterized by "Chinese-letter" patterns of trabecular bone without osteoblastic rimming [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1208-1209.

Q: All of the following are true about chordoma, except?

Endothelial origin. **Explanation:** **Chordoma** is a rare, slow-growing, but locally aggressive malignant bone tumor. The correct answer is **Option A** because chordomas are of **notochordal origin**, not endothelial origin. They arise from persistent remnants of the fetal notochord. * **Why Option A is the Exception:** Chordomas are ectodermal/neuroectodermal derivatives. Histologically, they are characterized by **physaliphorous cells** (large cells with bubbly, vacuolated cytoplasm) embedded in a myxoid stroma. They express epithelial markers like **Cytokeratin** and **EMA**, as well as the specific transcription factor **Brachyury**, which is a highly sensitive and specific diagnostic marker. * **Option B (More common in males):** This is a true statement. Chordomas show a slight male predilection, typically occurring in the 40–60 age group. * **Option C (Sacrococcygeal region):** This is true. The most common site is the **sacrococcygeal region (50%)**, followed by the spheno-occipital (clivus) region (35%) and the mobile spine (15%). * **Option D (Expansile lytic lesion):** This is true. Radiologically, they appear as destructive, expansile lytic lesions often associated with a large soft-tissue mass and irregular calcifications. **High-Yield Pearls for NEET-PG:** 1. **Brachyury:** The most specific diagnostic marker for chordoma. 2. **Physaliphorous cells:** The classic "soap bubble" appearance on histology. 3. **Location:** It is the most common primary malignant tumor of the sacrum. 4. **Prognosis:** Though slow-growing, they have a high rate of local recurrence after surgical excision.

Question 1

Hyperglycemia is associated with which of the following bone tumors?

Accepted Answer

Chondrosarcoma

Answer

Osteosarcoma

Answer

Chondroblastoma

Answer

Osteoma

Question 2

Marked reduction in the amount of dentin, widening of predentin layer, and presence of large areas of interglobular dentin are characteristic features of which condition?

Accepted Answer

Regional odontodysplasia

Answer

Dentinogenesis imperfecta

Answer

Amelogenesis imperfecta

Answer

Osteogenesis imperfecta

Question 3

Abnormal resorption followed by apposition of bone leaving deeply stained lines, which occurs in Paget's disease. These lines are known as:

Accepted Answer

Reversal lines

Answer

McGregor lines

Answer

Campbell's lines

Answer

None of the above

Question 4

A 50-year-old patient presents with enlarged knuckles and large subcutaneous nodules near her elbows. Her proximal interphalangeal (PIP) joints are hyperextended, and her distal interphalangeal (DIP) joints are flexed. If the nodules were biopsied, which of the following would best describe their likely histological appearance?

Accepted Answer

Fibrinoid necrosis surrounded by palisading epithelioid cells

Answer

Amorphous crystalline mass surrounded by macrophages

Answer

Cystic space caused by myxoid degeneration of connective tissue

Answer

Darkly pigmented synovium with an exuberant, villous growth

Question 5

Fibrous dysplasia associated with intramuscular myxoma is known as:

Accepted Answer

Maza rahe syndrome

Answer

Hans Schuller disease

Answer

Marfan Syndrome

Answer

Ehlers-Danlos syndrome

Question 6

What is the status of sweat gland function in cystic fibrosis?

Accepted Answer

Increased

Answer

Decreased

Answer

No change

Answer

May increase or decrease

Question 7

Which of the following tumors commonly metastasizes to lymph nodes?

Accepted Answer

Angiosarcoma

Answer

Osteosarcoma

Answer

Fibrous histiocytoma

Answer

Rhabdomyosarcoma

Question 8

What is the mechanism of transmission for Alpha-1 antitrypsin deficiency?

Accepted Answer

Autosomal recessive

Answer

Autosomal dominant

Answer

X-linked recessive

Answer

X-linked dominant

Question 9

All of the following are true about chordoma, except?

Accepted Answer

Endothelial origin

Answer

More common in males

Answer

Occurs in the sacrococcygeal region

Answer

Expansile lytic lesion

Question 10

Fish hook pattern of capillaries is seen in which of the following?

Accepted Answer

Hemangiopericytoma

Answer

Capillary hemangioma

Answer

Cavernous hemangioma

Answer

Angiosarcoma

Bone and Soft Tissue Pathology — MCQs

Bone and Soft Tissue Pathology — MCQs

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