Aspiration cytology of mesenchymal hamartoma of the chest wall: a case report and literature review.

Mesenchymal hamartoma of the chest wall is a rare tumor-like lesion of infancy and childhood. The few available descriptions of the findings on fine needle aspiration list spindle-shaped cells and cartilage or chondromyxoid material as essential features for this diagnosis. An aggressive appearance on imaging studies and a lack of familiarity with this lesion, can lead the pathologist to misdiagnose the cytologic findings as malignancy. We reported a 5-month-old male presenting with a mass of the right chest wall progressively for 2 months. Radiologic studies showed a mixed solid and cystic mass originating from the third, fourth and fifth ribs, and a diagnosis of malignancy was favored. Fine needle aspiration recovered only spindle-shaped cells and a few multinucleated giant cells of osteoclast type. After a review of the imaging, a diagnosis of mesenchymal hamartoma of the chest wall was raised. This diagnosis was confirmed by pathologic examination of the subsequently resected mass. This is the sixth report of a mesenchymal hamartoma of the chest wall diagnosed by fine needle aspiration. This case illustrates that this diagnosis can be suspected in the absence of cartilage or chondromyxoid material, given appropriate clinical and radiologic findings.