Follicular cutaneous T-cell lymphoma: a clinicopathological study of nine cases

Nine patients with follicular cutaneous T-cell lymphoma (CTCL), a recently described variant of lymphoma, are presented. On the basis of clinical mani festations and disease course, three groups of patients were distinguished: (i) two patients with follicular CTCL not associated with conventional les ions of mycosis fungoides (MF) and showing no evolution towards MF in follo w-up periods of 3 and 6 years; (ii) one patient; with follicular CTCL that evolved into conventional MF within 3 years; (iii) six patients showing con ventional MF lesions either before or concurrently with the follicular lesi ons and thus representing follicular CTCL of the true MF type. The follicul ar lesions included hair-devoid patches or plaques with spiky hyperkeratoti c papules (four patients), keratosis pilaris-like lesions (four), comedo-li ke lesions (four), follicular papules with alopecia (three) and milia-like lesions (three). Histopathological examination showed perifollicular and in trafollicular lymphocytes, without mucin deposition and with minimal or no involvement of the overlying epidermis. Significant syringotropism was also observed in three cases. Immunohistochemical analysis showed the predomina nce of CD4+ T cells, deletion of CD7 in some cases, Ki-67+ lymphocytes conf ined mainly to the follicular epithelium, and expression of keratinocyte in tercellular adhesion molecule-1 exclusively in the hair follicle. T-cell re ceptor gamma gene rearrangement was positive in the one case studied from e ach group. Different treatment modalities were employed, the most commonly used as monotherapy being phototherapy: psoralen ultraviolet A in four pati ents, two of whom showed a complete clinical and histopathological remissio n, and ultraviolet B in one patient, who showed a complete remission (both clinical and histopathological). This study indicates that follicular CTCL is more common than reflected in the literature, has heterogeneous clinical manifestations, and is either an expression of or closely related to MF. T he influence of the follicular involvement on the therapeutic response rema ins to be clarified. However, our therapeutic experience clearly suggests t hat some patients with follicular CTCL can benefit from phototherapy.