Widespread comedones as the sole clinical manifestation of follicular mycosis fungoides

ARTICLE

Auteur(s) : Tiago Torres, Gloria Velho, Rosário Alves, Manuela Selores

Department of Dermatology, Centro Hospitalar do Porto – Hospital de Santo António, Porto, Portugal. Edifício das Consultas Externas do Hospital Geral Santo António, Ex. CICAP, Rua D. Manuel II, s/n, 4100 Porto, Portugal

Mycosis fungoides (MF) is the commonest type of cutaneous T-cell lymphoma and can manifest with a variety of clinical presentations. Histologically, it is characterized by infiltration of the epidermis by medium-sized to large atypical T cells with cerebriform nuclei [1]. Hair follicle infiltration is a common histological feature of MF. It is usually clinically silent, however, folliculotropism-originated comedones, follicular keratosis, follicular papules and alopecia sometimes occur [2].

A 67-year-old man presented with disseminated comedones spread over the trunk, buttocks and thighs, mildly pruritic, with two years evolution (figure 1). There was no involvement of the head and neck area, and other cutaneous lesions, including patches, plaques, tumors or areas of alopecia were not present. Routine blood tests were within normal limits. Histopathology of the cutaneous lesions revealed a dense infiltrate of atypical lymphocytes surrounding the hair follicles, with some degree of folliculotropism but sparing the interfollicular epidermis. Alcian blue staining showed mucin deposition. The lymphocytes were mainly CD3⁺ and CD4⁺, with only a few CD8⁺ cells and isolated CD20⁺ B cells (figure 1). Staining for CD30 was negative. Molecular genetic analysis of the T-cell receptor γ-chain showed a clonal rearrangement in the tissue sections but not in peripheral blood mononuclear cells, confirming the diagnosis of Follicular Mycosis Fungoides. Further examination disclosed no extracutaneous involvement. The patient was diagnosed with stage IIB (T3N0M0) Follicular Mycosis Fungoides (FMF) and underwent treatment with INF α-2a (3 millions U 3 times/week) for 6 months, with an excellent response. Complete remission was achieved and maintained in the two-year follow-up.

FMF is considered an unusual clinical variant of MF in which the neoplastic lymphocytes surround and infiltrate the epithelium of the hair follicle, while sparing the epidermis. Clinically, it is characterized by comedones, follicular hyperkeratosis, follicular papules, cysts and plaques with follicular plugging. Usually, patients present clinically with various combinations of lesions. Rarely, as in our patient, a single type of lesions predominate and FMF cases in which comedones were the only presenting sign have been reported [3]. Clinical diagnosis may be difficult since the manifestations may look like acne or an acneiform eruption. It may require several biopsies to make a definitive diagnosis and sometimes the diagnosis may be only made by T-cell receptor gene rearrangement analysis [4]. Histopathologically, FMF is characterized by perifollicular and perivascular dermal infiltrates with variable infiltration of the follicular epithelium by medium-sized to large atypical T cells with cerebriform nuclei, sometimes accompanied by mucinosis. Infiltration of the interfollicular epidermis by atypical T cells is mostly absent (folliculotropism instead of epidermotropism). Generally, the neoplastic T lymphocytes are CD3⁺, CD4⁺ and CD8^-, as in classic MF [5]. The presence of a considerable number of CD30⁺ blast cells has been associated with a worse prognosis [4]. Because of the perifollicular localization of the dermal infiltrates, FMF is generally less responsive to the standard therapies used with classic MF and it is believed to have a worse prognosis. Total skin electron beam irradiation is the preferred method of treatment, but complete remission occurs in only a few cases and unresponsiveness has been reported. A good alternative can be found in PUVA combined with interferon-α, or retinoids [4]. A case of FMF treated with narrow band UVB has recently been reported [6]. Chemotherapy should be restricted to those patients with extracutaneous involvement [4].

Comedones as the sole manifestation of FMF is rare. The diagnosis in these cases requires a high clinical index of suspicion to give an accurate diagnosis at presentation. The authors emphasize the importance of considering FMF in the differential diagnosis of widespread comedones, particularly as the only clinical manifestation of the disease, and especially given the worse prognosis associated with the disease. An increased awareness of FMF should result in early diagnosis and therapy.

Acknowledgements

References

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