Benign Idiopathic versus Mycosis‐Fungoides‐Associated Follicular Mucinosis

Abstract

A study was undertaken in an attempt to identify useful histologic criteria that may allow differentiation between benign idiopathic and mycosis-fungoides-associated follicular mucinosis. We chose young patients because no person under 20 years of age with coexisting follicular mucinosis and mycosis fungoides disease has ever been reported. Our three most important observations in benign juvenile idiopathic follicular mucinosis were as follows: The lymphocytic infiltrate was generally confined to follicular, perifollicular, or perivascular zones with no extension of either normal or atypical mononuclear cells into the epidermis or into papillary/reticular dermis. Within follicular epithelium there were dense collections of lymphocytes with occasionally atypical-appearing nuclei in three of the eight patients, but never as Pautrier microabscesses. There was absence of a significant associated plasma cell or eosinophil-containing inflammatory dermal infiltrate. These findings are in contrast to those of older patients with follicular mucinosis and mycosis fungoides.

Mycosis fungoides with Mucinosis follicularis in Childhood

“…The etiology and pathogenesis remain unknown [19]. Follicular mucinosis is classified into two forms: a juvenile benign variant without an association with malignancy and an adult variant with a possible association with mycosis fungoides [18, 20]. Clinically the lesions frequently consist of follicular papules with a tendency to coalesce into one or several well-demarcated erythematous plaques.…”

Follicular Mycosis Fungoides, a Distinct Disease Entity With or Without Associated Follicular Mucinosis

“…The main criteria for diagnosis and for inclusion in the study were the presence of perifollicular-to-diffuse dermal infiltrates with variable numbers of atypical T cells with cerebriform nuclei infiltrating the follicular epithelium and the presence of mucinous degeneration of the follicular epithelium, as confirmed by Alcian blue staining of the first diagnostic biopsy specimens (diagnostic specimens). 6,7 Forty-nine patients met both criteria. Two cases with the same cytoarchitectural features in the diagnostic specimen but without associated follicular mucinosis were included as well.…”

Follicular Mucinosis

“…6,9 In fact, in the group of lymphoma-associated FM, 9 (32.1%) of the 28 patients showed histopathologic features suggestive of idiopathic FM, and 2 more presented with dense lymphoid infiltrates but without epidermotropism of lymphocytes. Conversely, in the idiopathic FM group, 6 (37.5%) of 16 patients revealed skin lesions with dense lymphoid infiltrates unusual for this type of FM and suggestive of a cutaneous lymphoproliferative process.…”

“…3,8,9,45 Another criterion proposed as helpful in the differential diagnosis is the molecular analysis of the TCRγ gene rearrangement. 46 However, several authors have pointed out the difficulty, or even impossibility, of clearly distinguishing the 2 groups.…”