Pancreatic neuroendocrine tumor in a child with a tuberous sclerosis complex 2 (TSC2) mutation

Pancreatic neuroendocrine tumors (PanNETs) are rare in children with tuberous sclerosis complex (TSC). The objective of this report is to describe a case of PanNET in a boy with TSC.

We describe the patient's clinical presentation, biochemical workup, and laboratory tests.

A 10-year-old boy with a TSC2 mutation presented with a nonsecretory PanNET discovered during routine annual abdominal ultrasound. Surgical distal pancreatectomy with spleen preservation was undertaken. The excised tumor appeared nodular, whitish, and encapsulated. The tumor was composed of pancreatic endocrine monomorphic cells, and the solid appearance of the tumor was interrupted by areas of cystic degeneration. Mitoses were rare; the proliferation index was estimated around 4%. Local lymph nodes showed hyperplasia but were free of metastatic disease. Immunohistochemical examinations were positive for the neuroendocrine markers chromogranin, neurospecific enolase, synaptophysin, CAM52, and vimentin and were negative for CD10 and alpha-1 antitrypsin. The immunohistochemistry also showed a lack of hyperactivation of mammalian target of rapamycin (mTOR) mTOR pathway. All data supported the diagnosis of a grade II well-differentiated neuroendocrine neoplasm, according to the World Health Organization (WHO).

Thirteen non-secretory PanNET cases associated with TSC have been reported, including our patient (9 men and 4 women; 7 with TSC2 mutation). These tumors are usually asymptomatic and can be associated with metastasis; therefore, early diagnosis is crucial for prompt treatment. It is still unclear whether PanNETs should be considered a feature of TSC; however due to this association, we suggest that pancreas investigation should be included in routine examinations in men with TSC2 mutation.