*Research Unit Dermatopathology, Department of Dermatology, Medical University of Graz, Graz, Austria †Department of Dermatology, University of Modena and Reggio Emilia, Modena ‡Department of Dermatology, Galliera Hospital, Genoa §Division of Dermatology, San Gallicano Dermatological Institute, Rome, Italy.
Am J Surg Pathol. 2016 Oct;40(10):1360-7. doi: 10.1097/PAS.0000000000000679.
Interstitial mycosis fungoides (IMF) is a rare histopathologic variant of mycosis fungoides (MF) that may mimic other inflammatory dermatoses, mainly interstitial granuloma annulare, inflammatory morphea, and interstitial granulomatous dermatitis. Only small series and sporadic case reports of IMF have been described in the literature. We reviewed 27 specimens from 21 patients with IMF (M:F=11:10, median age 60) to better characterize clinical, histopathologic, and immunohistochemical features of this disease. Most patients presented clinically with patches and/or plaques. Conventional MF was documented before, concomitant with, or after IMF in 12 patients, whereas only in 2 patients different biopsies showed exclusive features of IMF over a period of 4 and 191 months, respectively. Histology revealed in all cases variably long, linear aggregates of dermal lymphocytes splaying the collagen fibers, involving predominantly the superficial and mid-dermis (6 cases) or the entire dermis (21 cases). Immunohistochemical stainings revealed a cytotoxic phenotype in 9/18 tested cases. Variable amounts of histiocytes/macrophages were found interstitially in all tested biopsies but never represented a population larger than that of T lymphocytes. Our study shows that IMF is a peculiar variant of MF with frequent cytotoxic phenotype. This histopathologic variant in most cases represents a transient pattern in otherwise conventional MF. Accurate clinicopathologic correlation and phenotypic studies of atypical dermal interstitial lymphohistiocytic infiltrates allow to make a correct diagnosis.
间变性蕈样肉芽肿（IMF）是蕈样肉芽肿（MF）的一种罕见组织病理学变异型，可能模仿其他炎症性皮肤病，主要是间质性环状肉芽肿、炎症性硬皮病和间质性肉芽肿性皮炎。文献中仅描述了少量 IMF 的小系列和散发性病例报告。我们复习了 21 例 IMF 患者的 27 份标本（M:F=11:10，中位年龄 60 岁），以更好地描述该疾病的临床、组织病理学和免疫组织化学特征。大多数患者临床上表现为斑块和/或斑块。12 例患者在 IMF 之前、同时或之后记录了常规 MF，而只有 2 例患者在 4 个月和 191 个月的时间内，不同的活检显示 IMF 具有独特的特征。所有病例的组织学均显示真皮淋巴细胞呈不同长度的线性聚集，使胶原纤维呈扇形分布，主要累及真皮浅层和中层（6 例）或整个真皮（21 例）。免疫组织化学染色显示在 18 例检测病例中有 9 例具有细胞毒性表型。所有检测的活检中均发现数量不等的组织细胞/巨噬细胞，但从未代表比 T 淋巴细胞更大的群体。我们的研究表明，IMF 是 MF 的一种特殊变异型，常伴有细胞毒性表型。这种组织病理学变异型在大多数情况下代表了常规 MF 中的一种短暂模式。准确的临床病理相关性和对非典型真皮间质淋巴组织细胞浸润的表型研究有助于做出正确的诊断。
