Rectal Paraganglioma

A case report of primary colonic paraganglioma with lymph node metastasis

Background

Paraganglioma is a kind of neuroendocrine tumor that originates from paraganglia outside the adrenal gland. Gastrointestinal tract paraganglioma is very rare and only four cases of paraganglioma originating in the colon have been reported.

Case Presentation

We report a case of metastatic paraganglioma originating in the colon, in which the differential diagnosis was established by comprehensively considering clinical information, histology, immunohistochemistry, and findings of fluorescence in situ hybridization and next generation sequencing analyses. The patient has remained well for over 14 months after the treatment.

Conclusion

Since all paraganglioma have metastatic potential, we believe that radical surgical resection and regular follow-up are necessary. Genetic testing may be indicative of metastatic potential and prognosis. Because colonic paraganglioma is very rare, differential diagnosis is very important. Our report provides experience for the diagnosis and study of paraganglioma in rare sites.

Colorectal paragangliomas with immunohistochemical deficiency of succinate dehydrogenase subunit B

Recent progress in paraganglioma (PGL) revealed genotype-phenotype relationship, especially succinate dehydrogenase complex subunit B (SDHB) gene mutation-related to the extra-adrenal origin and metastasis. SDHB-immunohistochemistry can detect all types of SDH-subunit mutations, and is a useful tool to detect SDH-mutation tumors. PGLs usually occur along with sympathetic, and parasympathetic chains, however, colorectal paraganglioma is extremely rare. We have experienced one sigmoid colon PGL and one rectal PGL. These colorectal PGLs: a sigmoid colon PGL measuring 25 mm associated with a gastrointestinal stromal tumor (GIST) of the stomach, and a rectal PGL measuring 75 × 45 mm with elevated norepinephrine level were analyzed by immunohistochemistry for INSM1, chromogranin A, synaptophysin, tyrosine hydroxylase, dopamine-beta-hydroxylase, and SDHB and SDHA. The tumors were strongly positive for above markers, however, negative for SDHB. Both PGLs negative for SDHB immunohistochemistry were defined SDHB-deficient PGLs. Histologic grading of the PGLs by GAPP was well differentiated in sigmoid PGL versus poorly differentiated in rectal PGL. Although these PGLs were the same Stage II of TNM classification, the patient with sigmoid colon PGL had neither recurrence nor metastasis for 5 years after the operation, however, the patient with rectal PGL suffered the recurrent multiple metastases and expired 5 years after the operation. Herein, we compared these colorectal PGLs in regard to the patients' prognostic factors. Patient prognosis with these colorectal PGLs was mostly related to the tumor size and histologic grade under the same situation of SDH-deficiency.

A rare case of multiple paragangliomas in the head and neck, retroperitoneum and duodenum: A case report and review of the literature

Pheochromocytomas and paragangliomas (PGLs) are rare non-epithelial neuroendocrine neoplasms of the adrenal medulla and extra-adrenal paraganglia respectively. Duodenal PGL is quite rare and there are only two previous reports. Herein, we report a case of multiple catecholamines (CAs)-producing PGLs in the middle ear, retroperitoneum, and duodenum, and review the literature of duodenal PGLs. A 40-year-old man complained right-ear hearing loss, and an intracranial tumor was suspected. Magnetic resonance imaging of the head revealed a 3-cm mass at the right transvenous foramen, which was surgically resected following preoperative embolization. The pathological diagnosis was a sympathetic PGL of the right middle ear. Six years later, family history of PGL with germline mutation of succinate dehydrogenase complex iron sulfur subunit B, SDHB: c.268C>T (p.Arg90Ter) was clarified. The patient had elevated levels of plasma and urine CAs again. Abdominal computed tomography scanning revealed two retroperitoneal tumors measuring 30-mm at the anterior left renal vein and 13-mm at near the ligament of Treitz. The larger tumor was laparoscopically resected, but the smaller tumor was not identified by laparoscopy. After the operation, the patient remained hypertensive, and additional imaging tests suggested a tumor localized in the duodenum. The surgically resected tumor was confirmed to be a duodenal PGL. After that, the patient remained hypertension free, and urinary levels of noradrenaline and normetanephrine decreased to normal values. No recurrence or metastasis has been found at 1 year after the second operation. CAs secretion from PGLs in unexpected location, like the duodenum of our patient, may be overlooked and leads to a hypertensive crisis. In such cases, comprehensive evaluation including genetic testing, fluorodeoxyglucose-positron emission tomography scanning, and measurement of CAs will be useful for detecting PGLs. Most previous reports on duodenal PGL were gangliocytic PGL which has been renamed composite gangliocytoma/neuroma and neuroendocrine tumor, and defined the different tumor from duodenal PGL. We reviewed and discussed duodenal PGLs in addition to multiple PGLs associated with SDHB mutation.