It comes as no surprise to dermatologists that cutaneous T-cell lymphoma (CTCL) is associated with alopecia, especially in patients with follicular mucinosis (alopecia mucinosa), but how often does CTCL masquerade as alopecia areata (AA)?
Amin et al reported a 33-year-old female with a 7-year history of CD8-positive hypopigmented mycosis fungoides (MF) involving the trunk and extremities who presented with a large well-defined alopecic patch on her frontal scalp, resembling AA without hypopigmentation or erythema.1 A scalp biopsy revealed a non-scarring inflammatory alopecia and a superficial band-like atypical lymphoid infiltrate with prominent epidermotropism. Atypical, predominately CD8-positive lymphocytes were seen surrounding and infiltrating the bulb portion of several hair follicles. Treatments for her MF lesions included topical bexarotene, corticosteroids (topical and intralesional), and phototherapy, with very minimal hair regrowth. The authors noted that alopecia due to cutaneous lymphoma is an uncommon phenomenon but can occur in erythrodermic MF or Sézary syndrome (SS). AA-like changes have most often been reported in conventional patch/plaque-stage MF and folliculotropic MF. In those cases, the atypical lymphoid infiltrate is comprised predominately of CD4-positive lymphocytes. This is a rare report of a CD8-positive MF causing AA-like changes. The authors concluded by noting the importance of a scalp biopsy in patients with a history of cutaneous lymphoma presenting with alopecia in order to evaluate the nature of their hair loss.
It is hard to argue with that conclusion; however, AA is an extraordinarily common problem. I usually do not biopsy these lesions if the clinical appearance is classical, be it AA, alopecia totalis (AT), or alopecia universalis (AU). In the context of a known diagnosis of CTCL, such as in Amin’s case, a clinician could easily be suspicious of CTCL. What about classical cases without a known diagnosis of CTCL?
Iorizzo et al presented the case of a 27-year-old woman with clinically appearing AA of the pubic region.2 The initial biopsy demonstrated the characteristic “swarm of bees” of perifollicular and intrafollicular lymphocytes of AA. She did not respond to intralesional steroids. After 6 months, she developed papules within the alopecic site, which proved to be folliculotropic MF. A review of the original biopsy with deeper horizontal sections demonstrated a patchy, band-like infiltrate in the papillary and mid-dermis, at the level of the infundibulum and isthmus, characteristic of a patch-stage MF.
Bi et al, in a retrospective study, reported that, among 1550 patients with MF/SS, 2.5% (38 patients; aged 22 to 76 years, median of 51 years) with patchy, total-scalp, or universal alopecia were identified.3 Of these 38 patients, 13 (34%) had patchy alopecia clinically identical to AA. Scalp biopsy specimens were available in 5 of the 13 patients. Specimens from 4 patients had atypical T lymphocytes within the follicular epithelium or epidermis, and, of those patients, 2 demonstrated a histology of follicular mucinosis. The remaining 25 of 38 (66%) patients with MF/SS included 20 with alopecia within discreet patch/plaque or follicular lesions of MF and 5 with total-body hair loss, which presented only in those with generalized erythroderma and SS. AA-like hair loss on the scalp was the most common, affecting 8 of 13 patients. Bilaterally symmetric alopecia on the extremities was the second most common, affecting 6 patients—4 had involvement of both the upper and lower extremities, 1 had involvement of only the lower extremities, and 1 had involvement of only the upper extremities. Facial involvement (ie, eyebrows, eyelashes, beard) occurred in 3 patients, and truncal involvement occurred in 2. Approximately half developed alopecia and skin symptoms within 1 year of each other, whereas the other half developed alopecia more than 1 year after the onset of skin symptoms of MF. This finding suggests that alopecia may be an early sign of MF and that biopsy may help to make the correct diagnosis. To keep this in perspective, the prevalence of self-reported MF/SS was 0% in an AA database of 5000 individuals.3 In my PubMed search, I did not find any reports of AA in children with CTCL.
CTCL has earned its place in the pantheon of dermatologic mimickers, joining the ranks of syphilis and sarcoidosis. You can never be wrong adding MF to your clinical differential diagnosis. I will still not rush to biopsy classical AA, especially in children. When presenting as an adult, however, it is yet another reason to perform a full body skin examination—you might look at that alopecic area somewhat differently in the context of cutaneous lesions suggestive of CTCL. It might also be reasonable to consider a biopsy in classical lesions that are not responding to therapy as we might expect. I would still be surprised to find CTCL, but I won’t be flabbergasted!
Written by Warren R Heymann MD