Eosinophilic folliculitis, eosinophilic dermatosis of hematologic malignancy and acneiform follicular mucinosis: Two case reports and a review of the literature highlighting the spectrum of histopathology.

Within the literature, there is overlap in the histopathological features described in eosinophilic folliculitis associated with chronic lymphocytic leukemia (CLL), eosinophilic dermatosis of hematologic malignancy, and acneiform follicular mucinosis. These disorders are described with varying degrees of superficial and deep lymphocytic and eosinophilic inflammation demonstrating perivascular, perifollicular, and folliculocentric involvement with or without follicular mucin deposition. Given significant histopathological overlap, these diagnoses may represent a continuum on a spectrum of dermatoses. Here, we present two cases with histopathological elements that reflect components of this clinicopathological spectrum and compare our findings with previously reported cases to compare and contrast reported features. Our first case is a 71-year-old African American man with long-standing CLL who developed a pruritic erythematous papular eruption on the face and chest with biopsy revealing a dense folliculotropic lymphocytic infiltrate with conspicuous eosinophils and follicular mucinosis. Our second case is a 70-year-old Caucasian man recently diagnosed with CLL/small lymphocytic lymphoma who developed an erythematous papular rash on the neck and face with biopsy revealing superficial and deep perivascular and periadnexal lymphocytic inflammation with scattered eosinophils. Characterization of our two cases and comparison with available literature suggest that these disorders may represent a continuum of dermatoses.

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.

Juvenile-Onset Early-Stage Mycosis Fungoides-Associated Follicular Mucinosis: A Case Report.

We report a juvenile case of mycosis fungoides with prominent follicular mucinosis (FM). The patient was a 9-year old boy who presented with a 2-month history of enlarging alopecic patch with fine scales on the scalp. Dermatologic examination revealed orange-tan slightly palpable plaques with follicular prominence on his trunk. The patient and his family were not aware of these asymptomatic truncal plaques. Histopathologic examination of both-scalp and trunk-lesions revealed folliculotropic lymphocytic infiltration with mucin. Immunohistochemical study showed that lymphocytic infiltration was CD4 dominant. Flow cytometry analyses of peripheral blood were normal. Any abnormal populations and Sézary cells were not observed on blood smear. Polymerase chain reaction testing showed monoclonality for the T-cell receptor4-[Latin Small Letter Rams Horn] gene. Our patient had the clinical and histopathological diagnosis of follicular mycosis fungoides-associated follicular mucinosis.

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.

Follicular lymphomatoid papulosis with follicular mucinosis: a clinicopathologic study of 3 cases with literature review and conceptual reappraisal.

Lymphomatoid papulosis (LyP), characterized by recurring, waxing and waning, cutaneous papulonodules, is increasingly recognized to represent a heterogeneous collection of pathologically dissimilar subtypes. Recently, a follicular LyP variant was proposed, featuring folliculotropism. Folliculotropism by atypical lymphocytes is conventionally associated with follicular mucinosis and mycosis fungoides (MF), and review of the literature suggests co-occurrence of folliculotropism and follicular mucinosis in LyP to be rare, with only 3 cases identified to date. Herein we describe 3 additional cases, each manifesting a typical LyP clinical picture, with the additional element of folliculotropism and follicular mucinosis on pathology. These cases suggest that LyP should be considered alongside MF in the differential diagnosis of follicular mucinosis with accompanying atypical lymphocytic infiltration. As LyP can occur with other lymphoproliferative disorders such as MF, the finding of follicular mucinosis in LyP may further represent a conceptual intersection between the 2 disease processes.

Follicular mucinosis: an important differential diagnosis of leprosy in an endemic area.

Primary follicular mucinosis is a rare dermatosis characterized by the accumulation of mucin in the follicular epithelium and sebaceous glands. Clinically, it is characterized by the presence of papules or well-circumscribed and infiltrated plaques. In this paper, we report the case of a female patient, seven years old, evolving for three months with an asymptomatic, erythematous and infiltrated plaque located in the chin region. The research of thermal, pain and tactile sensitivity was inconclusive. Histological findings confirmed the diagnosis of follicular mucinosis. There was regression of the lesion with the use of medium potency topical corticosteroids for 20 days. The pathogenesis of follicular mucinosis remains unknown, being in some cases associated with lymphoproliferative disorders. In endemic areas of leprosy, isolated and infiltrated follicular mucinosis lesions should be further differentiated from leprosy.

Idiopathic follicular mucinosis or mycosis fungoides? classification and diagnostic challenges.

In recent years, the distinction between idiopathic follicular mucinosis (FM) and lymphoma-associated follicular mucinosis (LAFM) has been made through assessment of T-cell receptor gene rearrangement, flow cytometry, and immunohistochemistry. These methods, among others, have mostly identified monoclonality as a defining characteristic of LAFM; however, this finding cannot be considered conclusive, as monoclonality also has been described in benign inflammatory dermatoses such as lichen planus and idiopathic FM. Pure histologic diagnosis also is unreliable in many cases, as the histologic patterns of idiopathic FM and LAFM overlap. In this article, we discuss the importance of close clinical follow-up in patients with patch-stage mycosis fungoides (MF) or FM who have had a nondiagnostic histopathologic evaluation. We also highlight the value of ancillary testing, including T-cell receptor gene rearrangement, flow cytometry, and immunohistochemistry, as a component in the diagnostic process rather than the sole diagnostic moiety. Diagnosis and classification of idiopathic FM and LAFM continue to pose challenges for dermatologists, oncologists, and pathologists, and no single diagnostic tool is sufficient in providing diagnostic certainty; rather, a collective evaluation of pathologic, molecular, and clinical criteria is required. Currently, classification of idiopathic FM and LAFM incorporates clinical information and histologic assessment, but little consideration is given to the implications of the diagnosis from the patient's perspective. Revisiting histologic classification of these entities while incorporating the patient's perspective may prove beneficial to dermatologists as well as patients.

Well differentiated neuroendocrine tumor of the appendix and low-grade appendiceal mucinous neoplasm presenting as a collision tumor

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Follicular mucinosis: an important differential diagnosis of leprosy in an endemic area

Primary follicular mucinosis is a rare dermatosis characterized by the accumulation of mucin in the follicular epithelium and sebaceous glands. Clinically, it is characterized by the presence of papules or well-circumscribed and infiltrated plaques. In this paper, we report the case of a female patient, seven years old, evolving for three months with an asymptomatic, erythematous and infiltrated plaque located in the chin region. The research of thermal, pain and tactile sensitivity was inconclusive. Histological findings confirmed the diagnosis of follicular mucinosis. There was regression of the lesion with the use of medium potency topical corticosteroids for 20 days. The pathogenesis of follicular mucinosis remains unknown, being in some cases associated with lymphoproliferative disorders. In endemic areas of leprosy, isolated and infiltrated follicular mucinosis lesions should be further differentiated from leprosy.

Childhood follicular mucinosis co-existed with alopecia universalis.

We report a case of a 6-year-old girl presented with diffuse scalp and body hair loss and developed multiple groups of follicular papules on the trunk. She was diagnosed as follicular mucinosis co-existed with alopecia universalis. Histopathological study supported the diagnosis and did not find malignancy cells.

The clinical features and histopathologic patterns of folliculotropic mycosis fungoides in a series of 38 cases.

BACKGROUND: The recognition of folliculotropic mycosis fungoides (FMF) may pose diagnostic challenges, owing to the variety of histopathological findings. OBJECTIVE: In this study, our aim is to describe the broad spectrum of the histopathological patterns in a total of 86 biopsies from 38 patients with FMF, together with the clinical features. RESULTS: The most frequent histopathologic pattern was the folliculocentric/folliculotropic pattern, with or without follicular mucinosis. Keratin-filled cysts and comedones were the second most common pattern in the biopsies. Other less common findings included widening of the hair follicle orifis with keratotic plugging, reminiscent of keratosis pilaris, granuloma formation, eosinophilic or suppurative folliculitis and basaloid folliculolymphoid hyperplasia. Coexisting syringotropism was present in some biopsies. The CD4 : CD8 ratio was at least 4 : 1 or more in most biopsies. Grouped follicular papules and patch/plaque lesions with follicular prominence were the most frequent clinical findings. Folliculocentric lesions such as milia, cysts and acneiform lesions, alopecia, loss of hair or eyebrows were also seen. In 6 out of 38 (15.8%) patients, transformation to large-cell lymphoma was observed during the follow-up. CONCLUSION: The awareness and the identification of the various histopathological presentations of FMF by pathologists, as well as by clinicians, are imperative to prevent diagnostic errors.

Follicular mucinosis associated with nonlymphoid skin conditions.

BACKGROUND: Follicular mucinosis coexisting with lymphoproliferative disorders has been thoroughly debated. However, it has been rarely reported in association with inflammatory disorders. METHODS: Thirteen cases have been retrieved, and those with cutaneous lymphoma or alopecia mucinosa were excluded. RESULTS: Follicular mucinosis was found in the setting of squamous cell carcinoma, seborrheic keratosis, simple prurigo, acne vulgaris, dextrometorphan-induced phototoxicity, polymorphous light eruption (2 cases), insect bite (2 cases), tick bite, discoid lupus erythematosus, drug-related vasculitis, and demodecidosis. Unexpectedly, our observations revealed a preponderating accumulation of mucin related to photo-exposed areas, sun-associated dermatoses, and histopathologic solar elastosis. The amount of mucin filling the follicles apparently correlated with the intensity of perifollicular inflammatory infiltrate, which was present in all cases. The concurrence of dermal interstitial mucin was found in 7 cases (54%). CONCLUSIONS: The concurrence of interstitial dermal mucinosis or the potential role of both ultraviolet radiation and the perifollicular inflammatory infiltrates in its pathogenesis deserves further investigations. Precise recognition and understanding of this distinctive, reactive histological pattern may prevent our patients from unnecessary diagnostic and therapeutic strategies.