Bone and Soft Tissue Pathology Practice Questions

Q: Achondroplasia shows which type of inheritance?

Autosomal dominant inheritance. ***Autosomal dominant inheritance*** - Achondroplasia is caused by a **mutation in the FGFR3 gene**, which is located on an **autosomal chromosome** (chromosome 4). - The disease manifests with only **one copy of the mutated gene**, hence it follows an autosomal dominant pattern. *X-linked dominant (XLD)* - X-linked dominant disorders are caused by mutations on the **X chromosome** and typically affect females more severely or frequently than males. - Achondroplasia does not show sex-linked inheritance patterns, as its causative gene is on an autosome. *Autosomal recessive inheritance* - Autosomal recessive disorders require **two copies of the mutated gene** (one from each parent) for the disease to manifest. - Achondroplasia can occur with only one copy of the mutated gene, distinguishing it from recessive inheritance. *X-linked recessive (XLR)* - X-linked recessive disorders primarily affect **males** and are carried by females, who are usually asymptomatic carriers. - The inheritance pattern of achondroplasia is independent of sex, ruling out X-linked recessive inheritance.

Q: A 40-year-old patient presented with a large, painless swelling in the retroperitoneal area. A biopsy from the lesion is shown in the accompanying image. Molecular analysis demonstrated a translocation t(12;16). What is the most probable diagnosis?

Myxoid liposarcoma. ***Myxoid liposarcoma*** - Characterized by the presence of a **t(12;16)** chromosomal translocation, which is a hallmark of myxoid liposarcoma [1]. - Typically presents as a **soft tissue mass** in the retroperitoneum, consistent with the patient's symptoms. *Pleomorphic sarcoma* - Usually lacks the specific **t(12;16)** translocation and may show a more aggressive histological appearance [1]. - Less likely in this case due to a more complex morphology and different clinical behavior. *Lipoma* - Benign adipose tumors that do not correlate with the **t(12;16** translocation [2]. - They typically present as **soft, mobile masses** and are not associated with retroperitoneal swelling of this size [2]. *Synovial sarcoma* - Generally characterized by a **t(X;18)** translocation, distinct from the t(12;16) found in myxoid liposarcoma [3]. - Primarily affects the **extremities** and often presents near joints, unlike retroperitoneal locations [3]. **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. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1222. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1225-1226.

Q: In Rheumatoid arthritis, which type of cells are prominently present ?

Macrophages. ***Macrophages*** - **Macrophages** are abundant in the inflamed synovial tissue of patients with **rheumatoid arthritis**, contributing significantly to inflammation and joint destruction [1]. - They produce various **pro-inflammatory cytokines** (e.g., TNF-̑, IL-1, IL-6) and enzymes that degrade cartilage and bone. *B cells* - While **B cells** play a role in **rheumatoid arthritis** by producing autoantibodies like **rheumatoid factor (RF)**, they are not the most prominently present immune cell type in the synovium compared to macrophages [2]. - Their presence is often concentrated in lymphocytic aggregates within the synovium [1]. *T cells* - **T cells**, particularly **CD4+ helper T cells**, are important in orchestrating the immune response in **rheumatoid arthritis** and are found in the inflamed synovium [2]. - However, **macrophages** are generally more numerous and critical for the sustained inflammatory destruction. *Dendritic cells* - **Dendritic cells** are **antigen-presenting cells** that initiate and shape immune responses in **rheumatoid arthritis**. - While present in the synovium, their numbers are generally lower than those of **macrophages** and **T cells**. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 677-678. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1212-1214.

Q: Most common age group affected by Osteosarcoma

10-20 years. ***10-20 years*** [1] - **Osteosarcoma** is the most common primary malignant bone tumor and has a bimodal age distribution, with peaks in **adolescence (10-20 years)** coinciding with rapid growth and secondarily in older adults [1]. - The peak incidence in adolescents is attributed to the increased osteoblastic activity during **pubertal growth spurts**, making these cells more susceptible to malignant transformation. *Up to 10 years* - While pediatric bone tumors can occur, osteosarcoma is **less common** in children under 10 compared to the adolescent age group. - Other bone tumors like **Ewing sarcoma** might be more prevalent in this younger age range, especially in early childhood [2]. *30-40 years* - This age group is generally **less affected** by primary osteosarcoma compared to adolescents and older adults. - The incidence significantly decreases after the adolescent peak and before the secondary peak in older adults. *Older than 45 years* - A secondary peak of osteosarcoma occurs in older adults, often associated with **Paget's disease of bone** or previous **radiation exposure** [1]. - However, the most prominent and common age group for osteosarcoma overall is still adolescents. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1198-1200. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 671-672.

Q: Which of the following is the most common mutation in Ewing's sarcoma?

Translocation 11; 22. **Translocation 11; 22** - The most common and characteristic genetic alteration in **Ewing's sarcoma** is a **balanced chromosomal translocation** between chromosomes 11 and 22, specifically **t(11;22)(q24;q12)**. - This translocation results in the fusion of the **EWS gene** (on chromosome 22) with the **FLI1 gene** (on chromosome 11), creating a novel **fusion oncogene (EWS-FLI1)** that drives tumor development. *Translocation X : 18* - This translocation, **t(X;18)(p11.2;q11.2)**, is characteristic of **synovial sarcoma**, a distinct soft tissue tumor, not Ewing's sarcoma. - It leads to the fusion of the **SS18 gene** with one of several **SSX genes** (SSX1, SSX2, or SSX4). *Activating mutation of cell surface protein* - While activating mutations in various genes can occur in cancers, a general statement about an "activating mutation of a cell surface protein" is not the specific, most common genetic hallmark for **Ewing's sarcoma**. - Ewing's sarcoma is defined by its characteristic **fusion oncogene**. *Missense mutation in EXTI* - A **missense mutation in EXTI** (exostosin glycosyltransferase 1) is associated with **hereditary multiple exostoses** (also known as multiple osteochondromas), a different genetic disorder. - This mutation is not a defining characteristic or common mutation found in **Ewing's sarcoma**.

Q: What is the most common site of metastasis in the skeleton?

Vertebrae. ***Vertebrae*** - The **vertebrae** are the most common sites of metastasis in the skeleton due to their **high blood supply** and involvement in various malignancies [1]. - This frequently leads to conditions such as **vertebral compression fractures** and is associated with significant **back pain** and neurological deficits [1]. *Skull* - While the **skull** can be involved, it is not the most frequent site for skeletal metastases, with the vertebrae being more common [1]. - Metastasis to the skull may present as **local pain** or **swelling**, but overall, it is less prevalent compared to vertebral involvement. *Femur* - The **femur** can be a site for metastasis, particularly in certain cancers, but it is less common than the vertebrae [2]. - Metastatic lesions in the femur are more often associated with **pathologic fractures** rather than being the primary site of metastasis [1]. *Tibia* - The **tibia** is also a possible site of metastatic spread, but this is rare compared to the vertebrae [2]. - Typically associated with **painful lesions**, the tibia's involvement often indicates advanced disease but is not a primary site like the vertebrae. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 674-675. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 671-672.

Q: Which condition characterized by multiple enchondromas AND hemangiomas is associated with an increased risk of developing chondrosarcomas?

Maffucci syndrome. ***Maffucci syndrome*** - **Maffucci syndrome** is a rare, non-hereditary disorder characterized by the presence of multiple **enchondromas** (benign cartilaginous tumors) AND **hemangiomas** (benign vascular tumors) - The combination of enchondromas with vascular lesions is diagnostic of Maffucci syndrome - A significant complication is malignant transformation of enchondromas into **chondrosarcomas**, with a risk of approximately **15-30%** - The presence of hemangiomas differentiates it from Ollier disease *Felty syndrome* - **Felty syndrome** is a complication of **rheumatoid arthritis**, characterized by the triad of rheumatoid arthritis, **splenomegaly**, and **neutropenia** - Not associated with enchondromas, hemangiomas, or chondrosarcomas - Its primary effects relate to immune dysfunction and increased infection susceptibility *Ollier disease* - **Ollier disease** is characterized by multiple **enchondromas** but WITHOUT hemangiomas (this is the key differentiating feature) - Also carries increased risk of chondrosarcoma transformation (25-50%), actually higher than Maffucci syndrome - Typically shows unilateral distribution - The absence of vascular lesions distinguishes it from Maffucci syndrome *None of the options* - Incorrect because **Maffucci syndrome** fits the description of having both enchondromas AND hemangiomas with chondrosarcoma risk

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.

Question 1

Achondroplasia shows which type of inheritance?

Accepted Answer

Autosomal dominant inheritance

Answer

X-linked dominant (XLD)

Answer

Autosomal recessive inheritance

Answer

X-linked recessive (XLR)

Question 2

A 40-year-old patient presented with a large, painless swelling in the retroperitoneal area. A biopsy from the lesion is shown in the accompanying image. Molecular analysis demonstrated a translocation t(12;16). What is the most probable diagnosis?

Accepted Answer

Myxoid liposarcoma

Answer

Lipoma

Answer

Synovial sarcoma

Answer

Undifferentiated pleomorphic sarcoma

Question 3

In Rheumatoid arthritis, which type of cells are prominently present ?

Accepted Answer

Macrophages

Answer

B cells

Answer

T cells

Answer

Dendritic cells

Question 4

Most common age group affected by Osteosarcoma

Accepted Answer

10-20 years

Answer

Up to 10 years

Answer

Older than 45 years

Answer

30-40 years

Question 5

Which of the following is the most common mutation in Ewing's sarcoma?

Accepted Answer

Translocation 11; 22

Answer

Translocation X : 18

Answer

Missense mutation in EXT1

Answer

Activating mutation of cell surface protein

Question 6

What is the most common site of metastasis in the skeleton?

Accepted Answer

Vertebrae

Answer

Femur

Answer

Tibia

Answer

Skull

Question 7

Which condition characterized by multiple enchondromas AND hemangiomas is associated with an increased risk of developing chondrosarcomas?

Accepted Answer

Maffucci syndrome

Answer

None of the options

Answer

Felty syndrome

Answer

Ollier disease

Question 8

In osteogenic sarcoma predominant histological finding is ?

Accepted Answer

Osteoid-forming tumor cells

Answer

Giant cells

Answer

Fibroblastic proliferation

Answer

Chondroblasts

Question 9

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 10

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

Bone and Soft Tissue Pathology — MCQs

Bone and Soft Tissue Pathology — MCQs

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