A 51-year old presented with a 6-month history of increasing pelvic/lower back pain with nocturnal waking and episodes of anorexia and vomiting.
Examination revealed right torticollis and Horner’s syndrome, and a large abdominal mass arising from the pelvis. Magnetic resonance and positron emission tomography imaging revealed A) a 14cm heterogeneous enhancing mass, abutting the left kidney with standardised uptake value max=2.9, B) a large heterogeneous enhancing pelvic mass C) mesenteric adenopathy standardised uptake value max=10.3 and D) 6cm right lung apex mass standardised uptake value max=4.3.
Computerised tomography-guided biopsy of lesion A was reported as neurofibroma with occasional atypia, lesion B a benign uterine leiomyoma and lesion C follicular Lymphoma world health organisation Grade 2.
Although she had been given the diagnosis of Neurofibromatosis Type-1 (NF1) 25-years previously following removal of an intradural extramedullary schwannoma she had no cutaneous stigmata of NF1. Genetic analysis of blood lymphocyte DNA identified a pathogenic variant in SMARCB1 confirming a diagnosis of schwannomatosis..
Following 6-months chemotherapy for lymphoma, surgery was performed to remove lesion A. Histology revealed a malignant peripheral nerve sheath tumour with areas of low and high-grade change. An incidental, well-differentiated small bowel neuroendocrine carcinoma was also excised. Close surveillance continues with no recurrence after six years. This case study describes a novel finding of three separate synchronous primary malignancies in a patient with schwannomatosis and a proven SMARCB1 pathogenic variant.