Pseudolymphomatous folliculitis - A clinicopathologic study of 15 cases ofcutaneous pseudolymphoma with follicular invasion

Citation
E. Arai et al., Pseudolymphomatous folliculitis - A clinicopathologic study of 15 cases ofcutaneous pseudolymphoma with follicular invasion, AM J SURG P, 23(11), 1999, pp. 1313-1319
Citations number
37
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Research/Laboratory Medicine & Medical Tecnology","Medical Research Diagnosis & Treatment
Journal title
AMERICAN JOURNAL OF SURGICAL PATHOLOGY
ISSN journal
0147-5185 → ACNP
Volume
23
Issue
11
Year of publication
1999
Pages
1313 - 1319
Database
ISI
SICI code
0147-5185(199911)23:11<1313:PF-ACS>2.0.ZU;2-Z
Abstract
We report the clinical, histopathologic, and immunohistologic features of 1 5 cases of pseudolymphomatous folliculitis (PLF). The patients comprised se ven males and eight females (mean age, 38.6 years; age range, 2-67 years). All patients had dome-shaped or flat-elevated nodules suggestive of cutaneo us lymphoid hyperplasias (CLHs). The lesions were solitary in all 15 cases, except in one case with duplex lesions. All lesions were located on the fa ce and measured less than 1.5 cm. In 14 cases with one lesion each, five le sions showed rapid regression after incisional biopsy, whereas the remainin g nine underwent excisional biopsy. In the case with duplex lesions, one re gressed spontaneously after excisional biopsy of the other. Histopathologic ally, all PLFs showed dense lymphocytic infiltrates from the dermis to the subcutis simulating cutaneous lymphomas. The walls of hair follicles in all cases were enlarged and irregularly deformed with their epithelium blurred by lymphocytic infiltrates; we called this change "activation" of hair fol licles. In nine cases, many atypical lymphocytes were intermingled; three o f these cases had been misdiagnosed as cutaneous T-cell lymphoma at other i nstitutions. Immunohistologically, 10 and 5 cases showed predominantly B ce lls and predominantly T cells, respectively. Remarkably, all lesions showed increased numbers of perifollicular histiocytes expressing anti-S-100 prot ein and CD1a, and seven lesions showed histiocytes in aggregates. We conclu de that PLF is a subset of CLH with characteristic clinical and pathologic features showing perifollicular clustering of T-cell-associated dendritic c ells with activation of pilosebaceous units. PLF is an entity to be differe ntiated from malignant lymphomas and other cutaneous pseudolymphomas.