TSC Research Article Summaries: Gastrointestinal
Pancreatic neuroendocrine tumors in patients with tuberous sclerosis complex
Larson AM, Hedgire SS, Deshpande V, Stemmer-Rachamimov AO, Harisinghani MG, Ferrone CR, Shah U, Thiele EA.
Clinical Genetics 82(6):558-563, 2012
What is the topic?
The pancreas is a small gland located behind the stomach and plays an important role in digestion and hormone function. Sometimes, pancreatic lesions may be observed by abdominal MRI in persons with TSC. The lesions have been assumed to be benign cysts (non-cancerous, fluid-filled sacks) or small pancreatic angiomyolipomas not requiring immediate treatment. However, pancreatic neuroendocrine tumors (PanNETs) have been documented in some people with TSC, and the authors wondered whether many TSC-associated pancreatic lesions might be PanNETs rather than cysts or angiomyolipomas. This is important because PanNET is a rare type of tumor that may be either malignant (cancerous) or benign.
What did the researchers hope to learn?
The researchers set out to determine the frequency of PanNETs in TSC; the clinical, radiological, and pathological characteristics of pancreatic lesions in TSC; and the association with TSC1 or TSC2 mutations.
Who was studied? The authors reviewed records from 219 individuals with TSC from the Herscot Center for Adults and Children with TSC at Massachusetts General Hospital (MGH) and 12 case reports published by other investigators between 1959 and 2009. The authors also reviewed clinical records accompanying 390 PanNET specimens at MGH, six of which were associated with TSC.
What did the researchers find? Compared to PanNETs in the general population, pancreatic lesions in the TSC group were generally solitary (a single lesion per person) and occurred more frequently and at a younger average age (26 years vs. 56 years). In TSC, the lesions were more frequently cysts rather than solid tumors. In the six TSC-associated PanNETS for which genetic data was reported, all six had mutations in the TSC2 gene. However, the sample is too small to rule out the possibility that PanNETs might also be associated with TSC1 mutations.
What were the limitations of the study? Risk of malignancy was difficult to assess because the number of cases was small and longer follow-up time is needed.
What do the results mean for you? The authors at MGH have changed their clinical practice for routine imaging in TSC from the more limited renal imaging to more complete abdominal imaging to capture the pancreas. Although the aggressiveness of these pancreatic lesions in TSC remains unknown, early detection of any such lesions is important to enable a discussion with your physicians about how to deal with lesions that might be PanNETs.