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Follicular mucinosis preceding primary cutaneous extranodal NK/T-cell lymphoma relapse: A case report

Year: 2025

Type: article

Abstract: Dear Editor, A 53-year-old man presented initially with a nonhealing ulcer on the right heel, and the skin [Figure 1a] pathology revealed extranodal NK/T cell lymphoma, nasal type (ENKTL) in 2022. The atypical medium-to-large atypical lymphoid cells were positive for CD3/CD56/CD30 and EBER in situ hybridization [Figure 1b and c]. His serum Epstein–Barr virus (EBV) viral load was 314 IU/mL. F-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET) showed intense hypermetabolic lesions at the right foot (SUVmax = 21.8) and right inguinal node, but the biopsy from the right inguinal node only revealed lymphoid hyperplasia. He underwent chemotherapy in July 2022 (SMILE regimen), concurrent chemoradiotherapy in August 2022 (weekly cisplatin + 44 Gy/20fx of 9 MeV electron beam), and chemotherapy from October 2022 to January 2023 (VIPD regimen). The right heel wound healed completely in March 2023. Follow-up PET in August 2023 showed no evidence of residual disease.Figure 1: (a) A nonhealing foot ulcer turned out to be extranodal NK/T cell lymphoma, nasal type. (b) H and E stain (4 × 10): Ulcer, necrosis, and perivascular medium-to-large atypical lymphoid cells. (c) EBER in situ hybridization (4 × 10): Atypical lymphoid cells are positive for EBER. (d) A whitish ulcerative plaque on the left inner upper lip. (e) H and E stain (4 × 10): Diffuse infiltration of lymphocytes, medium-sized histiocytoid cells and some eosinophils in the dermis with focal necrosis and a few large pleomorphic cells. (f) EBER in situ hybridization (4 × 10): Atypical lymphoid cells are positive for EBER.In July 2024, he had swelling of bilateral upper eyelids and erythematous infiltrative facial papules and plaques [Figure 2a and b]. Follicular mucinosis was diagnosed by histopathology, with exocytosis of some mononuclear cells into the follicular epithelium [Figure 2c]. Alcian blue confirmed the follicular mucin deposition [Figure 2d]. The lymphocytes were mostly CD3+/CD20 − T cells, without aberrant loss of CD5 or CD7. CD56 stain and EBV in situ hybridization were negative. CD4: CD8 ratio was 4:1. He was treated with oral antihistamines and topical mometasone and the lesion resolved in 2 weeks.Figure 2: (a and b) Infiltrative erythematous papules on the cheeks. (c) H and E stain (10 × 10): Lymphocytes exocytosis into the follicular epithelium and follicular mucinosis. (d) Alcian blue (pH 2.5) stain (10 × 10): Bluish follicular mucin deposition.In November 2024, swelling of lips and left neck with lip ulcer were noted for 2–3 weeks. Biopsy from the lip ulcer showed ENKTL [Figure 1d-f]. PET was done and suspected relapsed ENKTL involving the left aspect of the lip, left platysma, and bilateral upper- and lower-extremity muscles. Core needle biopsy from the neck soft tissue was performed, showing necrosis, with EBER + atypical cells. Recurrent ENKTL was favored. Allogeneic stem cell transplantation was scheduled. Follicular mucinosis has been associated with various cutaneous T-cell lymphoma (CTCL), most notably mycosis fungoides. Nonetheless, it can also be found in other CTCL including primary cutaneous CD30+ lymphoproliferative disorders, primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder, peripheral T-cell lymphoma, unspecified, or other non-CTCL hematologic malignancies.[1] It could also be the presenting sign of acute myeloblastic leukemia.[2] In our case, the mononuclear cells infiltrating the follicles were immunophenotypically and morphologically normal. This suggested that the follicular mucinosis preceding ENKTL relapse might be a nonneoplastic, inflammatory reaction or response to the underlying lymphoid malignancy. It was also consistent with a previous study, in which lymphoid atypia was only seen in 69%–79% of patients with mycosis fungoides or hematological malignancy-associated follicular mucinosis.[1] ENKTL is a rare type of CTCL[3] which is more common in Asians.[4] ENKTL has protean manifestation, including acneiform papules,[5] but articles documenting the association of follicular mucinosis and ENKTL are lacking. Our case suggested that the occurrence of follicular mucinosis in the setting of a patient in remission for ENKTL may be a harbinger of relapse of the disease. We believe that ENKTL may be added to the increasing list of hematologic and lymphoproliferative diseases that could be associated with follicular mucinosis. However, due to the rarity of cases, a direct causal relationship remains to be studied. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent form. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed. Data availability statement All data generated or analyzed during this study are included in this published article. Financial support and sponsorship Nil. Conflicts of interest Prof. Tsen-Fang Tsai, an editorial board member at Dermatologica Sinica, had no role in the peer review process of or decision to publish this article. All authors declared no conflicts of interest in writing this paper.

Source: Dermatologica Sinica

DOI: 10.4103/ds.ds-d-24-00283

Authors: Chang-Yu Hsieh, Tsen-Fang Tsai

Institutions: National Taiwan University, National Taiwan University Hospital

Language: English

Topic: Cutaneous lymphoproliferative disorders research

Subfield: Dermatology

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $70