Paraganglioma of urinary bladder: a clinicopathological features analysis of 23 cases

Abstract

Objective: To investigate the clinicopathological features, diagnosis, differential diagnosis and immunohistochemical (IHC) characteristics of paraganglioma of urinary bladder (PUB). Methods: The clinical and pathological data of 23 cases of PUB were collected at the Second Affiliated Hospital of Fujian Medical University (7 cases); Fujian Provincial Hospital (8 cases); Fujian Medical University Union Hospital (6 cases); and First Affiliated Hospital of Fujian Medical University (2 cases) from May 2010 to November 2018. IHC staining for CK, GATA3, CD56, Syn, CgA, S-100 protein, HMB45, SDHB, OCT3/4 and Ki-67 was done using EliVision method; and the relevant literature was reviewed. Results: There were 14 women and 9 men, aged ranged from 21 to 73 years (median 51 years). Clinically, patients presented with headache, vertigo, palpitation, hypertensive crisis during micturition, hypertension, blurred vision, gross hematuria and paroxysmal pallor. The tumor sizes ranged from 0.9 to 6 cm (mean2.5 cm). Macroscopically, most tumors were exophytic and well delineated within the lamina propria or muscularis propria. The tumors were firm and nodular and showed grayish-tan cut surface. Histologically,the tumor growth pattern was expansive or showed interpenetrating infiltrative growth within the lamina propria or muscularis propria; the tumor cells were typically arranged in distinctive nests (Zellballen) with organoid arrangement; pseudo-rosette were seen in some cases. The cells were rounded or polygonal and had rich, acidophilic or amphophilic cytoplasm and may contain pigmented granules and vacuoles; the nuclei were central or eccentric, with small nucleoli, although occasionally some nuclei were pleomorphic and hyperchromatic. Spindled sustentacular cells could be seen around the nests of tumor cells in some cases. There were abundant vessels that were fissure-like, hemangioma-like or dilated. By IHC, the tumor cells were positive for GATA3 (2/23), OCT3/4 (2/23), CD56 (22/23), Syn (23/23), CgA (22/23), S-100 (sustentacular cell, 23/23) and SDHB (23/23); and negative for CK and HMB45; Ki-67 index was 1%-5%. At follow-up, there was no recurrence or metastasis in 18 cases. Conclusions: The diagnosis of PUB relies on the morphologic and IHC features; but there may be histomorphologic heterogeneity. The most important differential diagnosis is invasive urothelial carcinoma. The tumor cells may show aberrant cytoplasmic expression of OCT3/4; there is no clear correlation between SDHB and OCT3/4 expression in the group.