Mimicry of sugar tumor and minute pulmonary meningothelial-like nodule to metastatic lung deposits in a patient with rectal adenocarcinoma.

Several reports have described different lung lesions mimicking primary or metastatic neoplasms. In this paper, we describe the different features of two uncommon and benign lung lesions mimicking metastasis from a primary large bowel adenocarcinoma. Our patient is a 75-year old female with a history of invasive rectal adenocarcinoma. One month after her surgery, she started complaining of coughing and shortness of breath. Clear cell sugar tumor and minute meningothelial-like nodules had been found incidentally and simultaneously during her chest x-ray. The diagnosis had been made based on morphology and was supported by a positive staining to a panel of immunohistochemical stains including CD34, vimentin, HMB45, melan A and S100. An ultra-structural examination was also performed and confirmed the presence of melanosomes in sugar tumor. The coexistence of lung sugar tumor and minute pulmonary meningothelial-like nodules has never been reported in the literature and an awareness of these lesions is essential to correctly diagnose and stage patients.