成人型外阴孤立性肥大细胞瘤临床病理观察

Adult-type solitary mastocytoma of vulva

目的探讨成人型外阴孤立性肥大细胞瘤的临床病理特点。方法报道1例成人型外阴孤立性肥大细胞瘤,回顾分析其临床和影像学表现及病理组织学特点,应用免疫组化及特殊染色进一步确认诊断,探讨其鉴别诊断。结果患者女性,23岁。发现外阴肿物长达18年。CT提示阴蒂海绵体异常增大;MRI示外阴部肿物表现为与周边肌肉信号相似,界清。核医学MIBG显像显示外阴部放射性增强,提示异位嗜铬细胞瘤;奥曲肽显像示生长抑素受体(-);核医学血池显像示外阴部肿物处未见示踪剂(99mTcRBC)异常摄取。巨检:单一灰白色结节,切面质地细腻,无包膜。镜检:相对一致的肿瘤细胞在真皮层纤细的纤维间隔间呈结节状生长,围绕血管和神经,瘤细胞胞质丰富,呈红色、颗粒状,胞核圆形、染色质致密,核分裂象罕见,肿瘤局部可见小淋巴细胞浸润。免疫组化:肿瘤细胞CD117、CD68,CD43和LCA弥漫强(+),α-AT和calretinin部分(+),Ki-67<1%,瘤细胞胞质甲苯胺蓝染色呈深紫红色。术后随诊98个月,肿瘤无复发和转移。结论成人型孤立性肥大细胞瘤是一种罕见的肥大细胞良性肿瘤,组织病理学诊断关键在于认识肥大细胞,结合免疫组化和甲苯胺蓝染色可以确诊。

Abstract： Objective To evaluate the clinicopathological features of aduh-type solitary mastocytoma of vulva. Methods Retrospective study was performed to analyse the clinical, radiological, and histopathological features of adult- type solitary mastocytoma of vulva. Immunohistochemical and special staining were used to further confirm the diagnosis. The diagnosis and differential diagnosis about solitary mastocytoma were discussed. Results The patient was a 23 year- old woman. The patient primarily presented with a vulva tumor as long as 18 years. CT scan showed the abnormal increased clitoris cavernous; MRI showed the vulva tumor with a clear boundary had analogous signal compared to surrounding muscle. The nuclear MIBG imaging showed a vulva radioactive enhanced image, which suggested a ectopic pheochromocytoma ; octreotide imaging showed no abnormal somatostatin receptor image ; the blood pool imaging showed the tumor had no abnormal uptake of tracer （99mTcRBC）. Macroscopically, single gray nodule without capsule were presented. Microscopically, the tumor cells grew in the thin fibrous septa and partly around the blood vessels and nerves in the dermal layer, with red or granular abundant cytoplasm and round or dense chromatin nuclei. Rare mitotic figures were found in tumor cells, but some small lymphocytes were easily detectable. Immunohistochemistry showed that the tumor cells were diffusely strong postive for CD117, CD68, CD43 and LCA; focally positve for c^-AT and calretinin; positve for Ki-67 〈 1%. Toluidine blue staining showed purple-red cytoplasm of the tumor cells. The patient without tumor recurrence and metastasis survived after following-up for 98 months. Conclusion This adult-type vulva solitary mastocytoma is a rare benign tumor. Histopathologic diagnosis depends on being familiar with morphology of the mast cell, and combined with immunohistochemistry and toluidine blue staining it can be diagnosed.