Published online Nov 28, 2013. doi: 10.3748/wjg.v19.i44.8151
Revised: September 27, 2013
Accepted: October 13, 2013
Published online: November 28, 2013
Paragangliomas typically develop in the extra-adrenal sites along the sympathetic and/or the parasympathetic chain. Occasionally, the tumors may arise in some exotic sites, including the head and neck region and the urogenital tract. Paraganglioma presenting as a primary rectal neoplasm has not been well described in the literature. Here, we report the first case of malignant paraganglioma arising in the rectum of a 37-year-old male. He presented to the clinic because of hematochezia with tenesmus. The anorectal digital examination and colonoscopic examination revealed a polypoid mass of the rectum, measuring approximately 4 cm in diameter. The overall morphology and immunophenotype were consistent with a typical paraganglioma. However, the tumor exhibited features suggestive of malignant potential, including local extension into adjacent adipose tissue, nuclear pleomorphism, confluent tumor necrosis, vascular invasion and metastases to regional lymph nodes. In conclusion, we present the first case of rectal malignant paraganglioma. Due to the unexpected occurrence in this region, malignant paraganglioma may be misdiagnosed as other tumors with overlapping features; in particular, a neuroendocrine tumor of epithelial origin. Because of the differences in treatment, separating paraganglioma from its mimics is imperative. Combination of morphology with judicious immunohistochemical study is helpful in obtaining the correct diagnosis.
Core tip: We report a rare case of malignant paraganglioma arising in the rectum of a 37-year-old male. To the best of our knowledge, the current case represents the first case of malignant paraganglioma arising in the rectum. Due to the unexpected occurrence in this region, rectal paraganglioma may be misdiagnosed as other common types of tumors with overlapping features; in particular, a neuroendocrine tumor of epithelial origin. Because of the differences in treatment, separating paraganglioma from its mimics is imperative.