Gangliocytic paraganglioma: a multi-institutional retrospective study in Japan

Abstract

BackgroundGangliocytic paraganglioma (GP) is an extremely rare benign tumor that commonly arises from the second part of the duodenum. Since GP exhibit neither prominent mitotic activity nor Ki-67 immunoreactivity, this tumor is often misdiagnosed as neuroendocrine tumor (NET) G1 (carcinoid tumor). However, patients with GP may have a better prognosis than patients with NET G1. This fact emphasizes the importance of differentiating GP from NET G1, but few studies have reported the epidemiology and histopathology of GP because of its rarity. To differentiate GP from NET G1 with ease, we conducted a multi-institutional retrospective study analyzing the morphometric and immunohistochemical features of this tumor.MethodsSince only a limited number of patients with GP could be identified in our institute, we conducted a multi-institutional retrospective study of GP in Japan, which was approved by the Ethics Committee of our medical institute. The obtained tissue sections underwent detailed morphometric and immunohistochemical analyses. Additionally, to differentiate GP from NET G1 with ease, immunohistochemical findings were compared.ResultsIn our examination of 12 cases of duodenal GP, we found that epithelioid cells of GP exhibited positive reactivity for progesterone receptor and pancreatic polypeptide, whereas tumor cells of NET G1 were completely negative reactivity for both. Additionally, although GP is considered to be an extremely rare NET, we found that four (40.0%) of the ten patients at our institute with duodenal NET G1 actually had GP.ConclusionsAlthough GP is regarded as a rare NET, our results suggest that it accounts for a substantial percentage of duodenal NETs. Additionally, confirmation of immunoreactivity for progesterone receptor and pancreatic polypeptide can assist in differentiating GP from NET G1.

Gangliocytic Paraganglioma: a Diagnostic Pitfall of Rare Neuroendocrine Tumor

“…Thus, we would like to emphasize the usefulness of immunohistochemical examinations using progesterone receptor and pancreatic polypeptide to differentiate them. Namely, typical epithelioid cell (a major component of GP)shows positive immunoreactivity with them, whereas tumor cell of NET G1 was negative for both immunohistochemistries [4,5]. We believe that these findings may be useful to differentiate GP from NET G1, including small specimen obtained from biopsy.…”

“…To differentiate GP from paraganglioma, pathologists should consider the primary tumor site and the existence of ganglion-like cell (paraganglioma lacks ganglion-like cells, and it is very rare in the duodenum) [4]. On the other hand, morphological differences between GP and somatostatinoma make differentiation easy, and immunoreactivity for progesterone receptor and pancreatic polypeptide which is discussed below may be useful to differentiate them [5].…”

“…To differentiate GP from paraganglioma, pathologists should consider the primary tumor site and the existence of ganglion-like cell (paraganglioma lacks ganglion-like cells, and it is very rare in the duodenum) [4]. On the other hand, morphological differences between GP and somatostatinoma make differentiation easy, and immunoreactivity for progesterone receptor and pancreatic polypeptide which is discussed below may be useful to differentiate them [5].Meanwhile, the most important differential diagnosis of GP is neuroendocrine tumor (NET) G1. Indeed, the patients with GP may have a better prognosis than the patients with NET G1, but GP has often been misdiagnosed as NET G1 owing to its morphological similar findings and low proliferative activity [4,5].…”

“…On the other hand, morphological differences between GP and somatostatinoma make differentiation easy, and immunoreactivity for progesterone receptor and pancreatic polypeptide which is discussed below may be useful to differentiate them [5].…”

The role of insulin-like growth factor binding protein-related protein 1 (IGFBP-rP1) in endometrial carcinoma

“…Previous investigations showed that IGFBP-rP1 also plays an important role in the neuroendocrine differentiation for certain type of tumor [26]. It has been largely accepted that tumor with neuroendocrine differentiation is one of the most important prognostic factors [27][28][29]. In the view of the neuroendocrine differentiation, investigations of IGFBP-rP1 in EC have greater significance.…”