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.

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

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Adult T-cell leukemia-lymphoma associated with follicular mucinosis.

Follicular mucinosis is frequently associated with follicular mycosis fungoides, but its association with adult T-cell leukemia-lymphoma (ATLL) is extremely rare. We report a case of a 50-year-old female patient with a history of ATLL, after multiple treatments, with residual/recurrent skin tumors in the forehead and legs. Biopsy of a skin tumor from the forehead revealed a perifollicular and intrafollicular atypical lymphoid infiltrate with abundant mucin deposition. Immunohistochemical stains showed that the atypical cells were positive for CD3, CD4, and CD25. Reverse transcription polymerase chain reaction performed on the tissue sections confirmed the presence of human T-cell leukemia virus in the biopsies of skin tumors. To our knowledge, this is only the third reported case of a follicular mucinosis in the setting of ATLL.

Pediatric case of primary cutaneous eosinophil-rich CD30+ anaplastic large-cell lymphoma with follicular mucinosis.

We report a pediatric case of primary cutaneous CD30 anaplastic large-cell lymphoma showing a combination of rare histopathologic features. The patient was a 14-year-old boy who had a solitary 2 × 1-cm ulcerated nodule with purulent discharge and undermined borders located in the right preauricular area that had been present for 3 weeks. Histopathologically, there was a dense, nonepidermotropic multinodular to diffuse infiltrate involving the reticular dermis and, focally, the subcutis. The infiltrate was composed of numerous eosinophils, neutrophils, small well-differentiated lymphocytes, and large pleomorphic and anaplastic cells. Eosinophils dominated the infiltrate. Focally, the infiltrate was accentuated around hair follicles, many of which manifested features of follicular mucinosis and/or collections of neutrophils in the follicular epithelium. Occasional hair follicles were partly destroyed by the infiltrate. A conspicuous feature was a prominent myxoid change in the stroma surrounding the hair follicles and eccrine glands. Immunohistochemically, the large lymphoid cells expressed CD2, CD3, CD4, and CD30.

Follicular mucinosis and follicular mycosis fungoides: clinicopathological evaluation of seven cases.

OBJECTIVE: Follicular mucinosis is a disease characterized by follicular degeneration and mucin accumulation. It can be seen in mycosis fungoides, although idiopathic or forms associated with other diseases are also known. Follicular mycosis fungoides is a type of mycosis fungoides with different clinicopathological and prognostic features. MATERIAL AND METHOD: Seven cases with follicular centered lesions and multiple biopsies (2-6) were included. Cases were evaluated according to their clinical, histological and immunophenotypical features and follow-up data. RESULTS: All cases were male, and the mean age was 40.3 (range 18-61). Clinical complaints were follicular prominence, erythema and alopecia at head and neck, trunk, and lower limbs. Follicular mucinosis (6/7), and dermal lymphoid infiltration showing minimal-intensive folliculotropism accompanied by eosinophils was seen. Lymphoid infiltration was composed of small-medium sized cells, with scattered hyperchromatic nuclei in six cases. In one case there was only minimal cytological atypia. Intense folliculotropism of atypical lymphocytes and dense dermal infiltration without follicular mucinosis was seen in one case. Local and/or systemic treatments were applied and partial remission was achieved histologically. In three cases new and increasing lesions were seen. Density of infiltration and atypia were increased. CONCLUSION: The findings supported the opinion that follicular mucinosis is an important finding seen in mycosis fungoides. There can be important differences concerning the amount of infiltration and degree of atypia. In cases where the density of infiltration associated with follicular mucinosis is not diagnostic for MF, there can be progression over time. Long-term follow up is necessary in such cases where the differential diagnosis is difficult.

Nevoid follicular mucinosis: a new type of hair follicle nevus.

Follicular mucinosis represents a term for a histopathologic reaction pattern in follicular epithelium. It is a characteristic of alopecia mucinosa. However, it may also occur in a variety of unrelated conditions. Epidermal nevi are considered to be hamartomatous disorders and they can show a predominant component of non-organoid (keratinocytes) and/or organoid nevi. All the cases of epidermal nevi described with mucin deposits until now are reported as mucinous nevus or mucinous eccrine nevus; in the first type of disorder, diffuse mucin deposition is only seen in the papillary dermis, and in the second type, the mucin is found around the proliferation of eccrine structures. We believe this is the first reported case of epidermal nevus along Blaschko's lines exhibiting typical microscopic findings of mucinosis exclusively distributed inside the follicular epithelia.

Pediatric primary follicular mucinosis: further evidence of its relationship with mycosis fungoides.

Follicular mucinosis (FM) is an uncommon reaction pattern in which the accumulation of mucin in the follicular epithelium is the main pathologic finding. FM may be idiopathic (primary follicular mucinosis [PFM]), in association with mycosis fungoides or cutaneous T-cell lymphoma, or in association with other neoplastic and inflammatory conditions. Herein we report a case of PFM with identical T-cell clone rearrangement at anatomically distinct sites, supporting the idea that some authors have proposed, that FM may represent a low-grade lymphoproliferative disease related to mycoses fungoides with favorable prognosis.

Adult T-cell leukemia/lymphoma with follicular mucinosis: an unusual histopathological finding and a commentary.

Follicular mucinosis is currently recognized as a histopathological finding characterized by the accumulation of mucin within follicular epithelium and is commonly associated with follicular mycosis fungoides (MF). We report the finding of follicular mucinosis in a cutaneous nodule of human T-lymphotropic virus type 1 (HTLV-1) associated adult T-cell leukemia/lymphoma (ATLL). The patient was a 69-year-old female of Caribbean descent with a history of ATLL who presented with erythematous nodules on the chest and abdomen. Histopathologic examination showed a pan-dermal infiltrate of medium-to-large sized atypical lymphocytes extending into follicular epithelium where they associated with large mucin deposits. Immunohistochemical stains showed that the atypical lymphocytes were positive for CD3, CD4 and CD25 and negative for CD30. Cutaneous lesions of ATLL, which often present histopathologically as an epidermotropic lymphoma with Pautrier-type collections, are often difficult to distinguish from MF. Until recently, lymphoma-associated follicular mucinosis seemed specific to MF and Sézary syndrome (SS), being reported only once in a lesion of ATLL. We report a second case of ATLL-associated follicular mucinosis to increase awareness of this possible association, and briefly review the literature of follicular mucinosis-associated hematologic malignancies, ultimately cautioning against the interpretation of all cutaneous lymphoma-related follicular mucinosis as MF/SS.

Follicular mucinosis: a clinicopathologic, histochemical, immunohistochemical and molecular study comparing the primary benign form and the mycosis fungoides-associated follicular mucinosis.

OBJECTIVES: To determine (i) whether primary (idiopathic) follicular mucinosis (PFM) and lymphoma-associated follicular mucinosis (LAFM) are distinct or related entities and whether there are reliable criteria that allow the two forms to be distinguished, (ii) the histochemical properties and consequently the type of mucin that accumulates in the follicle in PFM and LAFM, and (iii) whether there is any difference between the staining properties of mucin in patients with PFM and LAFM. METHODS: Thirty-one patients were divided into two groups. Group 1 comprised 20 patients with no associated mycosis fungoides or Sézary syndrome (PFM) and group 2 was made up of the other 11 patients who had clinicopathological evidence of cutaneous T-cell lymphoma (LAFM). The biopsy specimens of the patients were studied with histopathological, histochemical and immunohistochemical methods. Molecular biology studies were also performed. RESULTS: Patients with PFM were more frequently younger (mean age 39 years), women (F:M=3:1), and presented with a solitary lesion involving the head/neck area more often than patients with LAFM who were older (mean age 54 years), men (M:F=2:1), and presented with multiple lesions on areas of the body other than the head/neck area. As for histopathological findings, large cystic spaces filled with mucin and a slight perivascular and periadnexal polyclonal infiltrate of mostly non-atypical lymphocytes without epidermotropism and with an equivalent CD4+/CD8+ cell rate were more suggestive of PFM. On the contrary, patients with LAFM were more probably to present with a dense band-like infiltrate with some atypical lymphocytes and sign of epidermotropism, a prominent CD4+ immunophenotype and a monoclonal rearrangement of the infiltrate. Mucin proved to be a dermal-type mucin, composed of both hyaluronic acid and sulfated glycosaminoglycans. No differences were found in the composition of the follicular mucin in the PFM compared with LAFM. CONCLUSIONS: Although no single, indisputable feature can reliably differentiate PFM from LAFM and a considerable overlapping among the two groups exists, the use of multiple clinical, histological and immunopathological criteria associated with gene rearrangement analysis can be useful in evaluation of those patients.

Case of follicular mucinosis: nestin-expression in mucin-producing cells.

A 29-year-old Japanese man had an asymptomatic, solitary, indurated, erythematous plaque measuring 30 mm x 30 mm on his jaw that had been present for a month. The skin lesion had follicular hyperkeratosis, and lacked hair. A skin biopsy specimen showed a dense perifollicular infiltration composed of lymphocytes, with an admixture of eosinophils in the full thickness of the dermis. The hair follicles and sebaceous glands had reticular epithelial degeneration by mucoid material of the outer root sheath and sebaceous epithelium. The mucoid material stained with Alcian blue at pH 2.5. The clinical and histological features were consistent with the diagnosis of follicular mucinosis. On immunohistochemistry, the outer root sheath cells with reticular epithelial degeneration were nestin-positive and keratin 15-negative. These results suggest that the outer root sheath cells with reticular epithelial degeneration come from the nestin-positive, multipotent, hair follicle stem cells.

Hereditary cutaneous mucinosis in shar pei dogs is associated with increased hyaluronan synthase-2 mRNA transcription by cultured dermal fibroblasts.

Shar pei dogs are known for the distinctive feature of thick, wrinkled skin as a consequence of high dermal mucin content. Excessive dermal deposition of mucinous substance leading to severe skin folding, and/or to the more severe vesicular form characterized by dermal vesicles or bullae, is highly prevalent in this breed and is known as idiopathic mucinosis. Hyaluronic acid (HA) is the main component that accumulates in the dermis, and high levels of HA have also been detected in the serum of shar pei dogs. In this study, the cellular and molecular mechanisms underlying cutaneous mucinosis of shar pei dogs were investigated. Thirteen shar pei dogs and four control dogs of other breeds were included. In primary dermal fibroblast cultures, transcription of the family of hyaluronan synthases (HAS) involved in HA synthesis, and of hyaluronidases (HYAL) involved in HA degradation, were studied by reverse transcriptase polymerase chain reaction. The location of HA in cell cultures was studied by immunofluorescence and confocal laser microscopy. Dermal fibroblasts transcribed HAS2, HAS3, HYAL1 and HYAL2, but no amplification for HAS1 was found. A higher transcription of HAS2 was demonstrated in shar pei dogs compared with control dogs. By confocal microscopy, HA was detected as a more diffuse and intense network-like pattern of green fluorescence in the fibroblast cells of shar pei dogs in comparison with control dogs. Together, these results provide additional evidence that hereditary cutaneous mucinosis in shar pei dogs may be a consequence of over-transcription or increased activity of HAS2.

CD44 and hyaluronate expression in follicular mucinosis.

BACKGROUND: CD44 is a membrane glycoprotein and the major cell-surface receptor of hyaluronate (HA). Lack of CD44 expression in mouse epidermis leads to an abnormal HA accumulation in the dermis, indicating an important role of CD44 in local HA metabolism. Decrease of epidermal CD44 expression in patients of lichen sclerosus et atrophicus is potentially responsible for dermal deposition of HA in this disease. Stromal HA accumulation is associated with decreased or lost expression of CD44 in perifollicular solitary cutaneous myxoma, myxoid dermatofibroma, and dermatofibrosarcoma protuberans. METHODS: We examined the expression of CD44 and HA in the skin biopsy specimens of 10 patients with follicular mucinosis by using CD44-specific antibodies and biotinylated HA-binding protein (HABP), respectively. RESULTS: No difference of CD44 expression was observed in the follicular keratinocytes when compared with those of unaffected interfollicular epidermis. The follicular zones of mucin deposition were strongly positive for HA. A weak interkeratinocyte staining for HA was also observed in the interfollicular epidermis. However, HABP staining revealed a stronger reactivity in the follicular keratinocytes surrounding the mucin-accumulated areas compared to the interfollicular keratinocytes. CONCLUSION: Our results suggest an active secretion of HA by follicular cells in follicular mucinosis.