Bone and Soft Tissue Pathology Practice Questions

Q: Which of the following conditions is characterized by joint hypermobility and hyperelasticity?

Ehlers-Danlos syndrome. **Explanation:** The correct answer is **Ehlers-Danlos syndrome (EDS)**. EDS is a heterogeneous group of heritable connective tissue disorders characterized by defects in the synthesis or structure of **fibrillar collagen** [1]. Because collagen provides the structural framework for skin, joints, and blood vessels, its deficiency leads to the classic triad of **joint hypermobility**, **skin hyperextensibility**, and **tissue fragility** (easy bruising/scarring) [1]. **Analysis of Options:** * **Marfan Syndrome:** Caused by a mutation in the **FBN1 gene (Fibrillin-1)**. While it presents with joint laxity and long limbs (arachnodactyly), its hallmark features are ectopia lentis (upward lens dislocation) and cardiovascular complications like aortic root aneurysm/dissection. It does not typically feature the extreme skin hyperelasticity seen in EDS. * **Fragile X Syndrome:** A genetic condition causing intellectual disability. While patients may have mild joint laxity and a long face with large ears, it is primarily a neurodevelopmental disorder caused by **CGG trinucleotide repeats** in the FMR1 gene. * **Angelman Syndrome:** A neurogenetic disorder ("Happy Puppet") caused by loss of function of the **UBE3A gene** on chromosome 15. It presents with ataxia, seizures, and frequent laughter, but not connective tissue laxity. **High-Yield NEET-PG Pearls:** * **Classical EDS (Types I/II):** Mutation in **COL5A1/COL5A2** (Type V collagen). Features "cigarette paper" or "papyraceous" scars. * **Vascular EDS (Type IV):** Mutation in **COL3A1** (Type III collagen). Most severe form; prone to spontaneous rupture of the aorta or hollow viscera (e.g., colon). * **Kyphoscoliotic EDS (Type VI):** Due to **Lysyl hydroxylase deficiency**; presents with ocular fragility and severe scoliosis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 154-156.

Q: The tissue of which lesion has been described as resembling a 'blood soaked sponge with large pores'?

Aneurysmal bone cyst. ### Explanation **Correct Answer: C. Aneurysmal Bone Cyst (ABC)** The description of a **"blood-soaked sponge"** is a classic gross pathological hallmark of an **Aneurysmal Bone Cyst (ABC)**. * **Pathophysiology:** ABC is a benign but locally aggressive osteolytic lesion characterized by blood-filled, cystic spaces separated by connective tissue septa [1]. * **Gross Appearance:** When the lesion is opened, the blood escapes, leaving behind a porous, honeycomb-like architecture that resembles a sponge saturated with blood. * **Microscopy:** The septa contain spindle cells, multinucleated giant cells, and reactive woven bone (osteoid), notably lacking an endothelial lining in the cystic spaces [1]. **Analysis of Incorrect Options:** * **A & B. Cavernous and Capillary Hemangiomas:** While these are vascular tumors, they consist of organized blood vessels lined by endothelium. A cavernous hemangioma contains large, blood-filled vascular channels, but it does not typically present with the "sponge-like" cystic architecture seen in bone pathology. * **D. Eruption Hematoma:** This is a soft tissue cyst (a variant of a dentigerous cyst) associated with an erupting tooth. It appears as a bluish, fluid-filled swelling on the gingiva, not a porous, sponge-like bony lesion. **NEET-PG High-Yield Pearls:** * **Radiology:** ABC typically presents as an **"eccentric, expansile, soap-bubble lesion"** with a "blow-out" appearance [1]. * **MRI Finding:** The presence of **fluid-fluid levels** (due to settling of RBCs) is a highly characteristic diagnostic feature. * **Genetics:** Look for the **USP6 gene rearrangement** on chromosome 17p13 in primary ABCs. * **Common Site:** Metaphysis of long bones and posterior elements of the vertebrae. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1206-1208.

Question 1

Which of the following conditions is characterized by joint hypermobility and hyperelasticity?

Accepted Answer

Ehlers-Danlos syndrome

Answer

Marfan syndrome

Answer

Fragile X syndrome

Answer

Angelman syndrome

Question 2

A 45-year-old man presents with back pain and facial pain. Physical examination reveals coarse facial features and kyphosis. Laboratory examination shows elevated alkaline phosphatase. Radiographic studies demonstrate skull thickening with narrowing of foramina, and bowing of the femur and tibia. Bone biopsy reveals a mosaic pattern of bone spicules with prominent osteoid seams. Which of the following neoplasms occurs with increased frequency in patients with this disorder?

Accepted Answer

Osteosarcoma

Answer

Astrocytoma

Answer

Hodgkin's lymphoma

Answer

Meningioma

Question 3

Renal osteodystrophy differs from nutritional osteomalacia by having which of the following?

Accepted Answer

Increased phosphates

Answer

Increased calcium

Answer

Decreased calcium

Answer

None of the above

Question 4

A sample to look for uric acid crystals (gouty tophus) would be submitted to the pathology laboratory in:

Accepted Answer

Alcohol

Answer

Formalin

Answer

Distilled water

Answer

Normal saline

Question 5

The tissue of which lesion has been described as resembling a 'blood soaked sponge with large pores'?

Accepted Answer

Aneurysmal bone cyst

Answer

Cavernous hemangioma

Answer

Capillary hemangioma

Answer

Eruption hematoma

Bone and Soft Tissue Pathology — MCQs

Bone and Soft Tissue Pathology — MCQs

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