Hyperplasia of Hair Follicles and Other Adnexal Structures in Cutaneous Lymphoproliferative Disorders

Abstract

We studied 53 cutaneous lymphoproliferative disorders, all of which manifested hair follicle hyperplasia. There were 42 cases conforming to the description of pseudolymphomatous folliculitis (PLF) and 11 cases of authentic lymphomas including mycosis fungoides, CD30+ anaplastic large cell lymphoma, diffuse large B-cell lymphoma, B-cell small cell lymphoma/leukemia, and peripheral T-cell lymphoma, not otherwise specified. All patients with PLF clinically presented with a solitary nodule preferentially involving the face. Beside hair follicle hyperplasia, the typical features were a dense infiltrate of small well-differentiated lymphocytes, lymphoplasmacytoid cells, plasma cells, and epithelioid histiocytes forming tiny granulomas. Some unusual or worrisome features recognized included eccrine/apocrine duct hyperplasia, subcutis/muscle infiltration, lymphocyte "smudging," single file infiltration, and large atypical cells. Immunohistochemically, T-cell predominant cases dominated in the series. All 34 tested cases revealed a polyclonal pattern of kappa and lambda immunoglobulin (Ig) light chain expression. In 4 cases, scattered CD30+ cells were identified. Monoclonal rearrangements of T-cell receptor (TCR) and IgH genes were detected in 19 and 3 cases respectively, including 1 case with dual T-cell receptor/IgH rearrangement. Three of 30 tested cases proved positive for herpes simplex virus-1, whereas herpes simplex virus-2 always tested negative. Of 31 cases tested for Borrelia burgdorferi, 30 specimens were negative. In 9 cases, fluorescent in situ hybridization for t(11;18) and t(14;18) revealed none of the above translocations. The most common treatment modality was surgical removal. Forty patients with a mean follow-up of 3.7 years included 39 patients with no evidence of disease and 1 individual with local recurrence. The comparison of "clonal cases of PLF" and those with polyclonal population or in which clonality remained undetermined revealed no differences between the 2 groups in the clinical presentation, pathologic, and immunohistochemical features. We conclude that hyperplasia of hair follicles and other adnexa can be seen not only in the condition currently known as PLF, but also in genuine cutaneous lymphomas and may be just a happenstance secondary to a basic pathologic process.

Multiple nodules on the left cheek represented pseudolymphomatous folliculitis

“…Thereafter, only approximately 10 reports on PLF, including 76 cases, have been published; thus, it is considered to be a rare entity. According to those past reports, typical PLF is presented as a solitary, erythematous or violaceous, dome‐shaped or flat elevated nodule on the face, especially on the nose, cheek, eyelid, or forehead 4, 5. In many cases, the eruption is isolated 5, whereas our patient showed a relatively rare pattern of eruption, as the PLF manifested as multiple lesions.…”

“…According to those past reports, typical PLF is presented as a solitary, erythematous or violaceous, dome‐shaped or flat elevated nodule on the face, especially on the nose, cheek, eyelid, or forehead 4, 5. In many cases, the eruption is isolated 5, whereas our patient showed a relatively rare pattern of eruption, as the PLF manifested as multiple lesions. PLF occurs in a wide age range and both sexes 5; however, its tendency is yet to be elucidated because of the low number of reports.…”

“…In many cases, the eruption is isolated 5, whereas our patient showed a relatively rare pattern of eruption, as the PLF manifested as multiple lesions. PLF occurs in a wide age range and both sexes 5; however, its tendency is yet to be elucidated because of the low number of reports. To the best of our knowledge, no cases of spontaneous regression without any treatment (operation, biopsy, medication, etc.)…”

“…A variety of differential diagnoses, including epidermal cyst, chronic folliculitis, granuloma, basal cell carcinoma, sarcoidosis, and insect bite reaction must be considered 1, 5, with malignant lymphoma being one of the most important. Thus, careful histological and immunohistochemical examinations are needed for accurate diagnosis of PLF 1.…”

“…Arai et al 4 proposed histological criteria for diagnosis, including nodular dense lymphocytic infiltration from the dermis to subcutis, befitting the term pseudolymphoma, in which lymphocytes surround and infiltrate the pilosebaceous unit, and deform the walls. Kazakov et al 5 presented 42 cases of PLF in which hair follicles were enlarged and often distorted, with a dense diffuse lymphoid infiltration composed mainly of small well‐differentiated lymphocytes, occupying the whole dermis, though sparing of the epidermis was also observed. Immunohistologically, PLF can be divided into four groups: predominance of B cells, predominance of B cells with fairly numerous T cells, predominance of T cells with fairly numerous B cells, and predominance of T cells 4.…”