Teaching Case

An 82-year-old male patient was referred to the Emergency Department for left inter-scapular pain, lasting for one week.
His medical history included hypertension under treatment and right occipital haemorrhage.

Chest X-ray showed left pleural thickening and soft tissue injury on the fifth left rib (Fig. 1). Non-enhanced CT scan was performed to gain further information about the lungs. CT showed lesions involving the fifth left rib for its entire length and D3-D4 vertebras with spinal cord invasion (Fig. 2).
CT images showed left pleural effusion but no pulmonary parenchymal abnormalities. To investigate the neoplastic origin of the lesion, the observation was also extended to the abdomen and completed with contrast agent. We observed a large mass involving the mid-lower pole of the left kidney, showing heterogeneous enhancement with peripheral hypervascular areas and thrombosis with filling defect involving the left renal vein (Fig. 3-4). An MRI was acquired to better characterise the spinal cord involvement (Fig. 5).
Ultrasound-guided biopsy of renal and rib lesion revealed the diagnosis: clear cell renal cell carcinoma.

The prevalence of the malignant costal lesions is about 3-8%, and the most commonly found are metastasis and myeloma. They are usually associated with primary neoplasm like breast cancer, prostate gland, lung and kidney cancer (RCC) [2], as in this case, and they may be osteolytic, sclerotic or mixed [3].
Rib metastases are generally multiple and small: isolated ones are rare (0.7-2.5 %) [1], mainly in RCC, and they are hardly bigger than 5 cm. They can be considered an atypical primary cancer presentation, otherwise the classical presentation of RCC is haematuria (55%), abdominal pain (40%), and palpable abdominal mass (35%).
Conventional chest radiograph and CT scanning represent the best method for rib lesions evaluation. At imaging, they have blurred outlines and can break the cortical bone, and occupy near soft tissue [3].
Bone scintigraphy is widely accepted as the standard test to evaluate bone metastasis. Although highly sensitive, bone scintigraphy lacks specifity, while CT improves specifity [2]. Surgical treatment represents the best approach for isolated rib metastasis, requiring wide resection including the rib below and the one under the metastatic one [1].

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