Primary Effusion Lymphoma-like Lymphoma in a Patient with Neurofibromatosis Type 1

To date, there are only 15 case reports of lymphoma in patients with neurofibromatosis type 1 (NF1), a common autosomal dominant tumor predisposition syndrome. Here, we present the first report of a primary effusion lymphoma (PEL)-like lymphoma (PEL-L), which is a human herpes virus 8/Kaposi sarcoma herpes virus-unrelated PEL, in a 73-year-old woman with NF1. The woman presented with pleural effusion following surgery for a small intestinal gastrointestinal stromal tumor and a malignant peripheral nerve sheath tumor. We prepared cellblocks to accurately differentiate between PEL, PEL-L, and pyothorax-associated lymphoma, for establishing a starting point for treatment and for prolonging survival. Attention should be paid to malignant neoplasms in NF1 patients. Diffuse large B-cell lymphoma may not be a rare complication in these patients, although how NF1 promotes its development remains to be determined. PEL-L should be suspected when body cavity effusion is observed in elderly patients. If feasible, it should be treated via rituximab-containing chemotherapy, which according to the literature, results in longer survival times than does drainage or regimens consisting of cyclophosphamide, doxorubicin, vincristine, and prednisone.