Bone and Soft Tissue Pathology Practice Questions

Q: In osteogenic sarcoma predominant histological finding is ?

Osteoid-forming tumor cells. ***Osteoid forming tumor cells*** - The predominant histological finding in **osteogenic sarcoma** is the presence of **osteoid**, which indicates that the tumor cells are actively involved in bone formation [1]. - These **tumor cells** exhibit features of malignant **osteoblasts**, contributing to the characteristic appearance of the tumor [1]. *Giant cells* - While **giant cells** can be present in various bone lesions, they are typically associated with conditions like **giant cell tumor of bone**, not osteogenic sarcoma. - These cells are non-specific and do not reflect the **malignant osteoblastic nature** of osteogenic sarcoma. *Chondroblasts* - **Chondroblasts** are primarily involved in the formation of **cartilage**, and their presence would suggest conditions like **chondrosarcoma** rather than osteogenic sarcoma. - Osteogenic sarcoma is characterized by **osteoid formation**, not cartilage production. *Fibroblastic proliferation* - While **fibroblastic proliferation** can be seen in soft tissue tumors, it is not a hallmark finding in osteogenic sarcoma. - This histological feature does not indicate the presence of the **osteoid**, which is critical for diagnosing osteogenic sarcoma. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 673-674.

Q: A 40-year-old person presented with a swelling in the retroperitoneal area. A biopsy from the lesion is as shown below. Molecular analysis demonstrated t(12;16). What is the most probable diagnosis?

Myxoid liposarcoma. ***Myxoid liposarcoma*** - The presence of **t(12;16)** translocation is characteristic of myxoid liposarcoma, which is crucial for diagnosis [1]. - Typically presents as a **soft tissue mass**, often in the retroperitoneum, consistent with the patient's swelling [1]. *Pleomorphic sarcoma* - Does not specifically associate with **t(12;16)** translocation; it is more commonly associated with various genetic alterations [1]. - Typically presents as a **heterogeneous** and highly aggressive neoplasm, lacking the specific features noted in this case. *Synovial sarcoma* - More commonly associated with a **t(X;18)** translocation, not t(12;16), which rules it out in this context. - Usually presents around the **joints** and has a different histological pattern compared to liposarcoma. *Lipoma* - A benign tumor that typically does not involve significant genetic mutations like **t(12;16)** [1]. - Presents as a **soft, mobile mass** and does not generally occur in a retroperitoneal setting with this size [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. 1222-1223.

Q: A 20-year-old man presented with a complaint of a swelling of the wrist for the last two years. Histopathological examination showed spindle-shaped cells and Verocay bodies. What is the diagnosis?

Schwannoma. ***Schwannoma*** - Characterized by the presence of **spindle-shaped cells** and **Verocay bodies**, typical of schwannomas, which are tumors of peripheral nerve sheath origin [1,3]. - Commonly presents with **pain** and **local swelling** in affected areas, aligning with the patient's symptoms [2]. *Dermoid cyst* - Usually presents as a **cystic lesion** containing skin appendages but does not feature spindle-shaped cells. - Lacks the characteristic **Verocay bodies**, which help differentiate schwannomas [1]. *Lipoma* - Composed of **mature adipocytes**, presenting as soft, movable masses, but not associated with spindle-shaped cells. - Histopathological examination would not reveal **Verocay bodies**, making it distinct from schwannoma [1]. *Neurofibroma* - Typically associated with **plexiform growth patterns** and lacks the classic **Verocay bodies** seen in schwannomas [1]. - Often occurs in patients with **neurofibromatosis** and presents differently than the clinical scenario here [3]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Peripheral Nerves and Skeletal Muscles, p. 1250. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 727-728. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Peripheral Nerves and Skeletal Muscles, pp. 1248-1249.

Q: A 30-year-old male presents with swelling around the knee joint. Histopathological examination reveals many giant cells interspersed with mononuclear cells. What is the most likely diagnosis?

Giant cell tumour. ***Giant cell tumour*** - The presence of **giant cells** interspersed with **mononuclear cells** in the histopathological examination is characteristic of giant cell tumors [1], often found around the **knee joint** [1]. - Typically occurs in **young adults** and is associated with **subarticular bone lesions** that cause joint swelling [1]. *Osteosarcoma* - Generally presents with **extensive bone destruction** and **persistent pain**, along with a mass, not primarily giant cell formation. - Commonly involves individuals aged **10-20 years**, making it less likely in a 30-year-old male. *Ewing's sarcoma* - Characterized by **small round blue cells** on histology, often with **more aggressive behavior** and less prominent giant cells. - Typically affects the **pelvis** and **long bones**, rather than directly around the knee joint. *Chondrosarcoma* - Primarily characterized by **cartilage formation** with no prominent giant cells, often leading to a confusing diagnosis in imaging. - Usually occurs in **older adults** and does not typically present with predominant giant cells in histopathology. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1205-1206.

Q: Chordoma arises from:

Notochord. ***Notochord*** - Chordoma is a **rare, slow-growing malignant bone tumor** that originates from **persistent notochordal remnants**. - The notochord is a flexible rod-like structure that serves as the primary axial support during embryonic development, eventually becoming the **nucleus pulposus** of the intervertebral discs. *Pharyngeal bursa* - The pharyngeal bursa is a normal anatomical variant, a small recess in the **posterior wall of the nasopharynx**. - It is not associated with the development of chordomas. *Rathke's pouch* - Rathke's pouch is an **ectodermal invagination** from the roof of the primitive mouth (stomodeum) that gives rise to the **anterior pituitary gland**. - Tumors arising from remnants of Rathke's pouch are typically **craniopharyngiomas**, not chordomas. *Luschka's bursa* - This term is sometimes used to refer to a **pharyngeal bursa**, as mentioned in the first incorrect option. - It is not the origin of chordomas.

Q: Which tumor is characterized by the presence of cells that resemble tennis rackets?

Langerhans cell histiocytosis. ***Langerhans cell histiocytosis*** - This condition is characterized by **Birbeck granules** within the Langerhans cells, which have a distinctive **tennis racket-like appearance** on electron microscopy. - The cells are also positive for **CD1a** and **S-100** immunohistochemical markers. *Sarcoma botyroides* - This is a subtype of **embryonal rhabdomyosarcoma** typically found in mucosal sites, presenting as a polypoid, grape-like mass. - Its histology shows small, undifferentiated cells with primitive skeletal muscle differentiation, but **not tennis racket-shaped cells**. *Vaginal adenocarcinoma* - This is a rare malignancy of the vagina, often associated with **diethylstilbestrol (DES) exposure** in utero, presenting as glands. - The cells show glandular differentiation and produce mucin, but **lack Birbeck granules**. *Seminoma* - This is a germ cell tumor of the testis characterized by large, uniform cells with clear cytoplasm and prominent nucleoli, divided into lobules by fibrous septa containing lymphocytes. - There are **no tennis racket-shaped cells** or Birbeck granules associated with seminoma.

Q: All are features of Paget's disease except which of the following?

Affects only axial skeleton. ***Affects only axial skeleton*** - This statement is **FALSE** and therefore the correct answer to this "EXCEPT" question. - Paget's disease **can affect any bone in the body**, including both axial skeleton (spine, skull, pelvis) and appendicular skeleton (femur, tibia, humerus) [1]. - Common sites include: **pelvis (70%), spine, skull, femur, and tibia** [1]. - While it frequently affects axial bones, it is **not exclusive** to them. *Defect in osteoclasts* - This is a TRUE feature of Paget's disease. - The disease is characterized by **abnormal, hyperactive osteoclasts** with increased number of nuclei (up to 100 vs normal 3-5). - These osteoclasts show **excessive bone resorption activity** followed by disorganized bone formation [1]. - The primary defect involves **increased osteoclast activity and sensitivity to RANKL**. *Can lead to hearing loss* - This is a TRUE feature of Paget's disease. - Skull involvement can lead to **compression of cranial nerve VIII** (vestibulocochlear nerve) [1]. - Enlargement and disorganization of temporal bone can cause **conductive or sensorineural hearing loss**. - Occurs in approximately 30-50% of patients with skull involvement. *Can lead to bone cancer* - This is a TRUE feature of Paget's disease. - **Osteosarcoma** develops in approximately **1%** of Paget's disease patients. - Risk is higher in patients with **polyostotic disease** and long-standing involvement. - This is a rare but serious complication with poor prognosis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1192-1194.

Q: What is the most common malignant tumor of the skeletal system?

Metastasis. ***Metastasis*** - **Skeletal metastasis** is overwhelmingly the most common malignant tumor involving bone, as many primary cancers (e.g., breast, prostate, lung) frequently spread to bone [1]. - While not originating in the bone, these metastatic deposits are malignant neoplasms within the skeletal system, making them the most prevalent. *Multiple myeloma* - This is a **primary malignancy of plasma cells** that arises in the bone marrow, causing destructive bone lesions. - It is the most common **primary malignant bone tumor** in adults, but still less common than metastatic disease. *Osteosarcoma* - This is the most common **primary malignant bone tumor** in **children and adolescents**, primarily affecting long bones [2]. - While a significant primary bone cancer, its incidence is lower than that of metastatic bone disease across all age groups [1]. *Chondrosarcoma* - This is a malignant tumor of **cartilage-forming cells** and is the second most common primary bone cancer in adults, after multiple myeloma [3]. - It is much less common than metastatic disease and osteosarcoma [1], [3]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 671-672. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1202. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1204.

Question 1

In osteogenic sarcoma predominant histological finding is ?

Accepted Answer

Osteoid-forming tumor cells

Answer

Giant cells

Answer

Fibroblastic proliferation

Answer

Chondroblasts

Question 2

A 40-year-old person presented with a swelling in the retroperitoneal area. A biopsy from the lesion is as shown below. Molecular analysis demonstrated t(12;16). What is the most probable diagnosis?

Accepted Answer

Myxoid liposarcoma

Answer

Benign lipoma

Answer

Synovial sarcoma

Answer

Pleomorphic sarcoma

Question 3

A 20-year-old man presented with a complaint of a swelling of the wrist for the last two years. Histopathological examination showed spindle-shaped cells and Verocay bodies. What is the diagnosis?

Accepted Answer

Schwannoma

Answer

Lipoma

Answer

Dermoid cyst

Answer

Neurofibroma

Question 4

A 30-year-old male presents with swelling around the knee joint. Histopathological examination reveals many giant cells interspersed with mononuclear cells. What is the most likely diagnosis?

Accepted Answer

Giant cell tumour

Answer

Osteosarcoma

Answer

Ewing's sarcoma

Answer

Chondrosarcoma

Question 5

Which statement is incorrect about the pathology of the bone tumor?

Accepted Answer

Chemotherapy is the treatment of choice for all bone tumors.

Answer

Tumor has distinct margin

Answer

Tumor arises from epiphyseal to metaphyseal region

Answer

Eccentric lesion

Question 6

Chordoma arises from:

Accepted Answer

Notochord

Answer

Pharyngeal bursa

Answer

Rathke’s pouch

Answer

Luschka's bursa

Question 7

All of the following are true regarding Paget's Disease except which of the following?

Accepted Answer

Cranial nerve involvement is not typically seen.

Answer

It may progress to a secondary chondrosarcoma.

Answer

Pelvis is the most common site for Paget's disease.

Answer

High output cardiac failure is a rare complication.

Question 8

Which tumor is characterized by the presence of cells that resemble tennis rackets?

Accepted Answer

Langerhans cell histiocytosis

Answer

Seminoma

Answer

Vaginal adenocarcinoma

Answer

Sarcoma botyroides

Question 9

All are features of Paget's disease except which of the following?

Accepted Answer

Affects only axial skeleton

Answer

Defect in osteoclasts

Answer

Can lead to hearing loss

Answer

Can lead to bone cancer

Question 10

What is the most common malignant tumor of the skeletal system?

Accepted Answer

Metastasis

Answer

Chondrosarcoma

Answer

Multiple myeloma

Answer

Osteosarcoma

Bone and Soft Tissue Pathology — MCQs

Bone and Soft Tissue Pathology — MCQs

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