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SHORT COMMUNICATION
A Case of Perforating Folliculitis Induced by Vemurafenib
Ken SHIRAISHI, Tae MASUNAGA, Mikiko TOHYAMA and Koji SAYAMA
Department of Dermatology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan. E-mail: [email protected]
Accepted Oct 3, 2018; E-published Oct 3, 2018
Vemurafenib, an oral BRAF kinase inhibitor, has been
approved for the treatment of late-stage metastatic
malignant melanoma. Although vemurafenib prolongs
progression-free and overall survival, numerous cuta-
neous side-effects have been reported (1, 2). We present
here a case of perforating folliculitis (PF) associated with
vemurafenib. To the best of our knowledge, this is the
first report of vemurafenib-associated PF.
CASE REPORT
A 62-year-old man was treated with vemurafenib (960 mg twice
daily) for metastatic malignant melanoma. Two months after ini-
tiating therapy, numerous disseminated keratotic follicular papules
developed on his scalp, face, trunk and legs (Fig. 1A, 3A). Each
papule contained a central, cone-shaped, keratotic plug (Fig. 1B).
Differential diagnoses included a perforating disorder, suppurative
folliculitis, hyperkeratotic folliculitis, and keratosis pilaris. Histo-
pathological examination showed a dilated follicular infundibulum
filled with a mixture of keratotic material, basophilic debris and
inflammatory cells (Fig. 2A). The follicular epithelium showed a
perforation through which degenerated collagen fibres entered into
the follicular cavity (Fig. 2B). The follicles were surrounded by
inflammatory infiltrate, mainly comprising lymphocytes. Elastic
Masson and Azan staining revealed invasion or penetration of
collagen fibres into the follicular epithelium (Fig. 2C, 2D). A
diagnosis of PF was established. Because of the clinical efficacy
against metastatic melanoma, vemurafenib
was maintained at the same dosage. Combined
treatment with topical corticosteroid ointments
and antibiotic ointments (nadifloxacin) did not
improve the folliculitis. We initiated minocy-
cline at 100 mg/day, but the skin lesions did
not disappear (Fig. 3B). After vemurafenib was
discontinued and changed to nivolumab due to
tumour recurrence, follicular papules rapidly
began to improve. One month after stopping
vemurafenib, the skin lesions disappeared with
residual pigmentation (Fig. 3C). We concluded
that PF was a cutaneous adverse drug reaction
due to vemurafenib.
Fig. 1. (A) Numerous disseminated keratotic follicular papules on the
trunk. (B) Each papule contained a central, cone-shaped, keratotic plug.
mas, palmar-plantar keratoses, and keratosis pilaris-like
eruptions, have been reported (1, 2).
Acquired perforating dermatosis is an uncommon
cutaneous perforating disorder characterized by trans-
epidermal elimination of dermal tissue materials, such
as keratin, collagen and elastic fibres. PF is an acquired
perforating dermatosis together with Kyrle disease,
DISCUSSION
Vemurafenib is a small molecule that
belongs to the group of protein kinase
inhibitors. The drug has been appro-
ved for the treatment of metastatic
melanoma harbouring the BRAF muta-
tion. Although vemurafenib prolongs
progression-free and overall survival,
numerous cutaneous side-effects, inclu-
ding photosensitivity, alopecia, xerosis,
squamous cell carcinoma, keratoacantho-
doi: 10.2340/00015555-3059
Acta Derm Venereol 2019; 99: 230–231
Fig. 2. (A) Dilated follicular infundibulum filled with a mixture of keratotic material, basophilic
debris and inflammatory cells. Haematoxylin and eosin staining; original magnification ×40.
(B) Degenerated collagen fibres enter the follicular cavity through the follicular epithelium.
Haematoxylin and eosin staining; original magnification ×100. (C) Elastic Masson staining reveals
invasion or penetration of collagen fibres (green); original magnification ×200. (D) Azan staining
detects collagen fibres (blue) invading into the follicular cavity; original magnification ×200.
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