An update on long-term outcomes of pediatric follicular mucinosis over a 20-year period: a retrospective cohort study.

BACKGROUND: Follicular mucinosis (FM) is a rare disease characterized by mucin accumulation in the follicular unit. FM's etiology is still widely debated since its first description in 1957. Follicular mucinosis is usually reported to be benign in children, although reports of malignant transformation, most commonly mycosis fungoides, exist. The present project aims to demonstrate that children with a diagnosis of follicular mucinosis have positive long-term outcomes and do not develop mycosis fungoides. MATERIALS AND METHODS: This is a retrospective cohort study where patients with a diagnosis of follicular mucinosis ages 22 years and below were identified. Data surrounding the patient's diagnosis of FM, differential diagnosis, treatments, and long-term outcomes were collected. Patients who were lost to follow-up were contacted by phone for an update on the status of their skin and overall health. RESULTS: Out of 14 patients with follow-up information, none developed subsequent mycosis fungoides or other hematologic malignancies. CONCLUSION: Pediatric patients with follicular mucinosis will likely present with limited disease and not experience malignant transformation.

Follicular mucinosis with novel dermoscopic finding: the toothpaste sign.

We describe a case of follicular mucinosis presenting with patchy alopecia affecting the eyebrows. On dermoscopy, white gelatinous material (presumed to be mucin) was visible along the hair shafts of the eyebrow lesions. We propose to call this novel dermoscopic finding the 'toothpaste sign'.

Follicular mucinosis: a review.

Follicular mucinosis (FM) is an epithelial reaction pattern characterized by follicular mucin accumulation. It has been described in association with various inflammatory and neoplastic cutaneous disorders. FM is generally divided into a primary benign idiopathic form and a secondary form usually occurring in association with cutaneous lymphomas (especially mycosis fungoides), among other entities. Distinction between the two forms can be challenging as they share many overlapping features and the lack of a single diagnostic tool to differentiate between the two. Making the distinction may require evaluating and correlating the clinical, histologic, immunohistochemical, and molecular studies together. Long-term clinical follow-up also remains very important. In this review, we describe the different entities associated with FM, its pathogenesis, and possible therapeutic options.

Follicular mucinosis in patients with hematologic malignancies other than mycosis fungoides: A clinicopathologic study.

BACKGROUND: Follicular mucinosis (FM), which is defined by mucin accumulation within follicular epithelium, may occur in mycosis fungoides (MF). FM without MF is occasionally reported in systemic hematologic malignancies and may be diagnostically challenging. OBJECTIVE: To describe clinicopathologic characteristics of FM in patients with hematologic malignancies other than MF. METHODS: Clinical data and histopathology features were analyzed in patients with FM and hematologic malignancies diagnosed between 1994 and 2017. RESULTS: A total of 18 patients with FM and systemic hematologic malignancies without cutaneous T-cell lymphoma (CTCL) were identified; 9 of them were discovered after hematopoietic stem cell transplantation. No patients with non-CTCL-associated FM (n = 46 [37 biopsy specimens]) developed CTCL during a mean follow-up of 4.3 years. Of the cases of CTCL associated with FM (n = 44 [31 biopsy specimens]), MF was the most common subtype (n = 38), although other CTCLs were identified. FM in patients with non-CTCL hematologic malignancies differed clinically from those with MF-associated FM, presenting most frequently with erythematous papules (P < .0001), without plaques (P <.0001), without alopecia (P = .001), and without histopathologically identified epidermal exocytosis (P = .013). LIMITATIONS: A retrospective study in a single cancer center. CONCLUSIONS: FM can present in systemic hematologic malignancies, including after hematopoietic stem cell transplantation. Papular lesional morphologic and histopathologic features may help to distinguish these cases from MF.

Acneiform follicular mucinosis: an indolent follicular mucinosis variant unrelated to mycosis fungoides?

Follicular mucinosis (FM) can present as an acneiform eruption, and is usually a benign variant of primary FM unrelated to cutaneous T-cell lymphoma (CTCL). We report two cases of women in their twenties who presented with an acneiform rash on the face, arms and back. In both cases, pathological evaluation of the facial papules revealed predominantly mucinous degeneration of the follicular epithelium, with insufficient lymphocytic infiltration or atypia to diagnose mycosis fungoides. These cases are similar to previous reports of acneiform FM. As none of the reported cases progressed to CTCL, we consider that overdiagnosis and overtreatment should be avoided in acneiform FM, but recommend long-term follow-up.

How to Discern Folliculotropic Mycosis Fungoides From Follicular Mucinosis Using a Pediatric Case.

Folliculotropic mycosis fungoides (FMF) is a variant of mycosis fungoides (MF) with folliculotropic, atypical lymphocytes that may or may not have mucin deposition surrounding the hair follicle. Follicular mucinosis (FM) is a primary or secondary finding in FMF, lupus, or collagen vascular diseases that is only a histological process of mucin deposition surrounding the hair follicles. We present a case of a 6-year-old boy who had features of both FMF and primary follicular mucinosis (PFM). The case reveals key insights on FMF with concurrent FM in pediatric patients and how to differentiate between FMF and PFM.