Chondrosarcoma in a Young Adult Male: A Radiologic Case-Based Review

 Chondrosarcoma in a Young Adult Male: A Radiologic Case-Based Review

Introduction

Chondrosarcoma is a malignant cartilage-forming tumor that can arise de novo or from pre-existing benign cartilage tumors such as enchondromas or osteochondromas. Although most frequently diagnosed in older adults, chondrosarcomas may affect younger individuals as well, particularly in the ribs, pelvis, or long bones. This blog post discusses the case of a 26-year-old man presenting with persistent right-sided chest pain and highlights the imaging features, differential diagnoses, and final pathology-confirmed diagnosis of chondrosarcoma. This article integrates high-traffic SEO keywords and is optimized for Google AdSense monetization.

Clinical Presentation

A 26-year-old man presented with several months of persistent right-sided chest pain unrelieved by NSAIDs or rest. He had no significant past medical history. The initial chest radiograph revealed an abnormal finding in the right anterior chest wall.

Figure 1. Chest radiograph showing an expansile lesion of the right third rib. Lungs are clear.

Initial Imaging and Findings

The chest X-ray (Figure 1) demonstrated an expansile lesion involving the right third rib. This warranted further evaluation with cross-sectional imaging.

CT Findings

Figure 2. Non-contrast CT shows a destructive, expansile lesion in the anterior right third rib with characteristic rings-and-arcs calcification suggestive of a cartilaginous matrix.

The CT scan confirmed a lytic, expansile mass in the anterior aspect of the third right rib with classic "rings-and-arcs" calcifications. There was cortical destruction but no definite soft tissue mass.

Bone Scan

Figure 3. Tc-99m MDP bone scan showing increased osteoblastic activity in the right third rib.

The bone scintigraphy revealed intense uptake at the lesion site, indicating increased metabolic activity suggestive of an aggressive lesion.

MRI Findings

Figure 4. Gadolinium-enhanced MRI demonstrating a lobulated lesion with peripheral enhancement. No invasion into pectoral muscles or pleura.

MRI revealed a 5 cm lobulated mass with peripheral and heterogeneous contrast enhancement. A secondary lesion in the sternum also showed enhancement, possibly representing a benign enchondroma or hemangioma.

Differential Diagnosis

The differential diagnosis for a rib lesion in a young adult includes:

• Chondrosarcoma

• Enchondroma

• Osteosarcoma

• Giant cell tumor

• Metastasis

• Langerhans cell histiocytosis

• Osteomyelitis

Final Diagnosis

The lesion was surgically excised and confirmed as chondrosarcoma on histopathology.

Discussion

Chondrosarcoma represents approximately 20% of primary bone malignancies. In ribs, it tends to involve the anterior costochondral junction and presents with pain or a palpable mass. Radiographically, chondrosarcomas often show cortical thinning or destruction, with a soft-tissue component and characteristic matrix mineralization. MRI is particularly useful for delineating tumor extent and its relation to adjacent structures.

Chondrosarcomas usually do not respond to chemotherapy or radiation and are managed primarily with wide surgical resection. Prognosis depends on the histologic grade and surgical margins.

Quiz Section

Question 1: What is the most likely diagnosis based on chest X-ray findings?
A. Fractured scapula
B. Left third rib lesion
C. Right third rib expansile lesion ✅
D. Left upper lobe atelectasis
E. Right upper lobe atelectasis
Answer: C. Right third rib expansile lesion
Explanation: The X-ray clearly shows expansion and lucency of the right third rib, consistent with a lesion.

Question 2: What is the key CT finding suggestive of chondrosarcoma?
A. Homogeneous soft tissue mass
B. Dense cortical bone
C. Rings-and-arcs calcification ✅
D. No calcification
E. Fat-density lesion
Answer: C. Rings-and-arcs calcification
Explanation: This pattern is highly characteristic of cartilaginous tumors.

Question 3: What does the Tc-99m MDP scan indicate?
A. Decreased osteoblastic activity
B. Normal bone metabolism
C. Increased uptake in the rib lesion ✅
D. Diffuse skeletal uptake
Answer: C. Increased uptake in the rib lesion
Explanation: Active lesions demonstrate increased tracer uptake due to high bone turnover.

Question 4: What are common imaging features of chondrosarcoma on MRI?
A. Hypointense on T2
B. Peripheral and heterogeneous enhancement ✅
C. No enhancement
D. Fat signal
Answer: B. Peripheral and heterogeneous enhancement
Explanation: Chondrosarcomas are typically hyperintense on T2 and enhance peripherally.

Question 5: Which of the following is NOT a typical differential diagnosis for rib lesions?
A. Chondrosarcoma
B. Enchondroma
C. Lung adenocarcinoma ✅
D. Giant cell tumor
Answer: C. Lung adenocarcinoma
Explanation: While lung adenocarcinoma may metastasize to ribs, it is not a primary bone lesion.

References

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