Case Reports

Primary chest-wall leiomyosarcoma: a rare mimic of a malignant rib lesion


Primary chest-wall leiomyosarcoma (LMS) is an uncommon, malignant, soft-tissue tumor that most often affects the extremities. Malignant LMS originates from mesenchymal cells with smooth muscle differentiation. It is rare in adults, forming only 7% of all soft-tissue sarcomas (STS), but it is the most common STS. In adults, this type of tumor is usually found in the retroperitoneum and extremities. 1 Chest-wall LMS is rare and most often occurs in men aged 50-70 years. 2 When LMS is associated with rib destruction, it may mimic a primary bone tumor or metastasis. We present here the case of histologically proven chest-wall sarcoma with associated rib destruction that was initially mistaken on imaging for either a metastasis or primary bone tumor.

Case presentation and summary
A 69-year-old man presented to the emergency department complaining of pain over the right side of the chest. The pain, which was pleuritic in nature, had worsened over the previous 6 months and was severe at presentation. The patient had no fever, shortness of breath, or loss of weight. He had no history of chest trauma or chest wall radiation, and nothing noteworthy was discovered in his medical history. Subsequent test results for hemoglobin, white blood cell count, lymphocyte count, and cardiac enzymes were normal.

A frontal chest radiograph showed an osteolytic destructive lesion involving the posterior right 6th rib (Figure 1). A contrast-enhanced computedtomography (CE-CT) scan of the chest showed a heterogeneously enhancing, ovoid, soft-tissue mass of 5.6 x 3.6 cm (2.2 x 1.2 in) centered on the postero- lateral right 6th rib, with associated rib erosion. There was another 2.0-cm (0.8-in) subpleural nodule in the left upper lobe (Figure 2).

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