A 61-year-old man presented with a 2-year history of painful mucosal lesions and pruritic violaceous plaques on the trunk and extremities. He had been repeatedly diagnosed with oral lichen planus and had received prolonged topical and systemic therapies, including corticosteroids, hydroxychloroquine, and herbal medicine, with minimal response and progressive worsening. Examination revealed diffuse erythematous-to-violaceous scaly patches and plaques on the trunk and limbs, hyperkeratotic plaques on the dorsal hands with nail thickening and longitudinal ridging, severe erosions and hemorrhagic crusting of the lips, Wickham striae on the buccal mucosa, and genital erythema with mild exudation (Fig. 1).
Laboratory testing showed mild anemia and reduced absolute T- and B-cell counts. Indirect immunofluorescence (IIF) and serologic evaluation for connective tissue disease and autoimmune blistering disease were negative. Skin biopsies from the lip and left hand showed lichenoid lymphocytic infiltration with basal vacuolar degeneration and pigment incontinence, supporting lichen planus (Fig. 2); direct immunofluorescence (DIF) was not performed. Positron emission tomography-computed tomography (PET-CT) revealed multiple lymph nodes with increased fluorodeoxyglucose (FDG) uptake. Flow cytometry detected aberrant T-cell populations in peripheral blood and bone marrow, while lymph node flow cytometry showed aberrant T lymphocytes accounting for 91.72% of lymphocytes. Lymph node biopsy demonstrated atypical lymphoid hyperplasia with vascular invasion; immunohistochemistry showed a predominantly CD4-positive T-cell infiltrate with scattered CD8-positive cells, and T-cell receptor gene rearrangement revealed clonality. Epstein–Barr virus-encoded RNA (EBER) was negative.
The final diagnosis was systemic peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), with extensive lichen planus-like mucocutaneous disease. The main diagnostic question was whether the eruption represented direct cutaneous involvement by lymphoma or a concomitant lichenoid disorder[
1]. Although systemic PTCL-NOS can secondarily involve the skin, the biopsied lesions showed lichenoid/interface dermatitis without atypical lymphoid infiltrates, prominent epidermotropism, or dense dermal tumor infiltrates. Because routine histopathology did not suggest lymphomatous infiltration, additional lymphoma-directed immunohistochemistry or T-cell clonality testing was not pursued on the skin specimens. Chronic oral involvement, Wickham striae, nail changes, and lichenoid histopathology supported a diagnosis of lichen planus-like disease. However, the unusually extensive distribution, poor response to conventional therapy, and systemic lymphadenopathy raised concern about an associated systemic disorder[
2,
3], prompting further evaluation that led to the diagnosis of PTCL-NOS. Lichenoid drug eruption was less likely because there was no clear temporal relationship with a new medication[
4]. Paraneoplastic pemphigus and other autoimmune blistering diseases were not favored, given negative IIF and blistering serology and absence of acantholysis, although DIF was not performed. Connective tissue disease was not supported by serologic testing or histopathology[
4].
The patient was referred to the hematology department and treated with combination chemotherapy consisting of cyclophosphamide, liposomal mitoxantrone, vindesine, and methylprednisolone[
5], alongside supportive dermatologic care. His cutaneous plaques and oral erosions improved substantially after treatment.
This case highlights a practical warning sign for dermatologists and oral medicine clinicians: presumed lichen planus-like disease that is unusually extensive or multisite, progressive and refractory to appropriate therapy, or accompanied by lymphadenopathy should prompt evaluation for an underlying malignancy. Imaging, lymph node biopsy, bone marrow assessment, and clinicopathologic correlation are important when disease behavior is atypical. Multidisciplinary collaboration between dermatology and hematology is essential for timely diagnosis and treatment planning.
PDF
(1642KB)
