hGH and GHR expression in large cell neuroendocrine carcinoma of the colon and rectum.

Large cell neuroendocrine carcinoma (LCNEC) is an aggressive neoplasm with a low frequency of occurrence in the digestive tract. We present a series of eight patients diagnosed with LCNEC of the colon and rectum. Grossly, tumors were presented as endophytic/ulcerative, annular and polypoid masses, with a gray-white color and necrosis in most cases. Histologically, they were high-grade tumors composed of large cells of organoid, nesting, trabecular, rosette-like and palisading patterns, with a high mitotic rate. Tumors were immunoreactive for neuroendocrine markers, including chromogranin A (2/8), synaptophysin (7/8), and neuron-specific enolase (8/8). Moreover, we analyzed the expression of growth hormone (hGH) and growth hormone receptor (GHR) in colorectal LCNECs and six tumors were immunoreactive for hGH, while five tumors were immunoreactive for GHR. To our knowledge hGH and GHR expression has not been previously analyzed in colorectal LCNEC. Their overexpression suggests a role of hGH and GHR in the development of colorectal LCNEC.