Primary Clear Cell Sarcoma of the Lung: a Case Report.

BACKGROUND

Clear Cell Sarcoma of Soft Tissue (CCSST), or melanoma of the soft part, is a rare, aggressive tumor that originates in the aponeurosis and fasciae of the distal parts of the extremities. Reports from other sites of the body are rare.

OBJECTIVE

We are reporting an extremely rare tumor that presented as a central left-sided lung mass and found to be clear cell sarcoma of soft tissue.

METHODS

We report a 24-year-old male patient presented with recurrent attacks of left-sided chest pain associated with cough and dyspnea.

RESULTS

Imaging showed a central left-sided 8*5.5*5 cm lung mass. The age of the patient and the radiological characteristics of the lesion were suggestive of a benign pathology. After histopathological assessment of the lesion, suspicion of the malignant process was raised, mainly melanoma of soft part and PEComa. The patient underwent left-sided pneumonectomy. The postoperative histological examination, immunohistochemical findings including positive staining for S-100, HMB-45, and Melan-A, and positive FISH study for EWSR1 gene rearrangements supported the diagnosis of CCSST originating primarily in the major fissure of left the lung.

CONCLUSION

The rarity of CCSST in general and tumors originating in the lung primarily raise the challenges in hypothesizing a differential diagnosis, choosing proper investigations and treatment methods. The histological examination, immunohistochemical, and cytogenetics of the tumor are mandatory to reach the final diagnosis.