Clear Cell Sugar Tumour

Abstract

A 56-year-old female smoker with a history of right breast cancer (T1N0M0) had an incidental finding of an 8-mm right lower lobe solitary pulmonary nodule on computed tomography scan. The lesion was not positron emission tomography avid; however, it slowly progressed in size on surveillance computed tomography to 11 mm. She proceeded to thoracotomy and right lower lobectomy with lymph node sampling. Histology confirmed a clear cell sugar tumour. Clear cell sugar tumour of the lung is a remarkably rare benign pulmonary neoplasm of perivascular epithelioid origin, and a member of the PEComatous group of tumours. PEComas of the lung are divided into lymphangioleiomyomatosis, benign PEComas (including clear cell sugar tumour), and malignant PEComas. PEComas can be found in other sites, including the female genital and gastrointestinal tracts. The tumours characteristically contain a large amount of glycogen; therefore, leading differentials to consider are metastatic renal cell carcinoma and clear cell pulmonary carcinomas. Diagnosis is established by demonstrating immunoreactivity for human melanoma black (HMB-45) and S-100 protein, with no reactivity for cytokeratin 7 or epithelial membrane antigen. The general recommendation is for surgical resection without adjuvant chemotherapy.