Follicular cysts and hyperkeratoses in early mycosis fungoides
Authors: van de Kerkhof P. C. M. 
Published: March 2003

A 63‐year‐old woman had a 50‐year history of “dry skin.” At the age of 43, she presented for the first time at the Department of Dermatology with follicular hyperkeratotic papules on the upper legs, nates, abdomen, and upper arms ( Fig. 1). Histopathologic investigation revealed follicular hyperkeratoses with a mononuclear infiltrate, partly invading the hair follicles. The condition was diagnosed at first as keratosis pilaris and subsequently as pityriasis rubra pilaris. At the age of 52, the patient was treated with acitretin (35 mg per day as initial dose and 10–25 mg per day as maintenance dose). The condition improved considerably with this treatment, which was continued for 6 months. Following discontinuation of treatment, the condition relapsed after 6 months.

Follicular hyperkeratoses on the upper legs

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At the age of 58, the condition was aggravated with the formation of poikiloderma on the trunk, upper arms, and neck with reticular hyperpigmentations, scaling, and erythema, yellow cysts on the shoulders, back, and face ( Fig. 2), palmoplantar keratoderma, and scarring alopecia with loss of scalp, pubic, and axillary hair. The hair on the arms and trunk was also markedly reduced. Within 1 year, the condition was complicated by indurated erythematosquamous plaques on the trunk, upper arms, and upper legs.

Cysts of the neck and face

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Histopathologic investigation of repeated biopsies taken from the erythematosquamous plaques revealed a dense infiltrate of T lymphocytes (predominantly CD4 positive cells with some hyperchromatic indented nuclei) with epidermotropism of the hair follicles and interfollicular epidermis and some Pautrier microabscesses ( Fig. 3). The epidermis was partly orthokeratotic and parakeratotic. Histopathologic investigation of the epidermal cysts revealed a picture of epidermal cysts filled with horn material and invaded by some lymphocytes. The follicular hyperkeratoses consisted of orthokeratotic material with

Histopathologic appearance of an erythematosquamous plaque on the leg, showing a dense lymphocytic infiltrate, with epidermotropism of the interfollicular and follicular epidermis and some hyperchromatic indented nuclei (haematoxylin and eosin, original magnification ×100)

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lymphocytes invading the follicular wall. No mycosis fungoides cells and no depositions of mucin were observed.

General investigation did not reveal pathologic lymph node, liver, or spleen enlargement. Routine blood investigations did not reveal abnormalities, in particular no Sezary cells, negative lues serology, and negative borrelia serology. Antinuclear factor and anti‐double‐stranded DNA were negative. X‐Ray examination of the thorax and computed tomography (CT) scan of the thorax and abdomen did not reveal abnormalities.

At the age of 58, the patient had a heart infarction and, for this reason, was treated with metropolol, 100 mg per day, and acetyl salicylic acid, 80 mg per day. Following discontinuation of metropolol, the skin condition did not improve.

Treatment with acitretin was reinstalled at the age of 59 and has been continued to the present. A marked improvement was observed, which persisted during maintenance treatment with acitretin (10–20 mg per day). Discontinuation of acitretin during 1 month resulted in severe aggravation of the erythematous and hyperkeratotic lesions, which necessitated reinstallation of this effective treatment. No side‐effects were observed apart from cheilitis.