Positron-emission tomography findings indicating the involvement of the whole body skin in subcutaneous panniculitis-like T cell lymphoma

Eyelid erythema as the first manifestation of subcutaneous panniculitis-like T-cell lymphoma mimicking dermatomyositis: a case-based review

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) which preferentially infiltrates into subcutaneous adipose tissue is rare, however may mimic autoimmune diseases from the aspect of clinical manifestations. Here, we describe a 16-year-old young man, who initially presented with eyelid erythema and swelling, accompanied by fever and muscle and bone marrow involvement. He was preliminarily considered as a patient with classical dermatomyositis (DM), but finally diagnosed as SPTCL concomitant with paraneoplastic inflammatory myositis, confirmed by in total 8 times repeated biopsies at different sites. After systematically reviewing the literatures, we summarized the main features of SPTCL mimicking DM with eyelid edema as the presenting manifestation. The cautionary tale reminds rheumatologists of considering mimickers in patients with atypical autoimmune-like manifestations. Suitable biopsy is critical for diagnosis and improving prognosis.

Report of Eleven Patients of Subcutaneous Panniculitis-Like T-Cell Lymphoma: Clinicopathologic Features, 18F-FDG PET/CT Findings and Outcome

Objectives

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a fairly rare subtype of primary cutaneous lymphoma. This study aims to investigate the clinicopathologic features, ¹⁸F-FDG PET/CT findings, and outcome of patients with SPTCL.

Methods

A retrospective single-center study enrolled 11 patients with SPTCL between August 2010 and March 2020. A total of 26 ¹⁸F-FDG PET/CT scans were performed, and the initial and follow-up PET/CT imaging features, clinicopathologic and immunohistochemical characteristics, and outcome were analyzed.

Results

The male-to-female ratio was 1.2. The mean age at diagnosis was 24.2 years (age range: 13-48 years). Histopathological examinations revealed atypical T-lymphocyte rimming of individual subcutaneous adipocytes, mostly with CD2⁺, CD3⁺, CD4^-, CD5⁺, CD8⁺, CD56^-, T-cell intracellular antigen-1⁺, Granzyme B⁺, and high Ki-67 index. Multiple large skin ulcerations with a maximum diameter of 10 cm were observed in one of the 11 patients (9.1%, 1/11), and hemophagocytic syndrome was found in another one. At initial PET/CT scans, the lesions in all 11 patients showed increased uptake of ¹⁸F-FDG with a wide range of maximum standard uptake value (SUVmax) from 2.0 to 14.9. The morphology of the lesions presented as multiple nodules and/or disseminated plaques mainly involving the trunk and/or limbs. Five patients had extracutaneous non-lymph node lesions with SUVmax of 5.6 ± 2.8 on ¹⁸F-FDG PET/CT. No significant correlation between SUVmax and Ki-67 index was observed (r = 0.19, P > 0.05). Follow-up ¹⁸F-FDG PET/CT scans in six patients showed complete remission of the disease in two, partial remission in three, and progressive disease in one. During the follow-up period, there was no death except for the patient with multiple ulcerations who died 4 months after diagnosis of SPTCL.

Conclusions

SPTCL may be a group of heterogeneous diseases with varying degrees of ¹⁸F-FDG uptake. ¹⁸F-FDG PET/CT demonstrates its usefulness in detecting disease extent, providing diagnostic work-up, staging, and evaluating treatment response of SPTCL. Multiple large skin ulcerations may be a factor of poor prognosis for patients with SPTCL.

Subcutaneous Panniculitis-like T Cell Lymphoma Mimicking Early-Onset Nodular Panniculitis

Patient: Male, 24

Final Diagnosis: Subcutaneous panniculitis-like T-cell lymphoma

Symptoms: Fever • skin nodules

Medication: —

Clinical Procedure: Skin biopsy • PET-CT

Specialty: Hematology

Bone marrow involvement by subcutaneous panniculitis-like T-cell lymphoma: a report of three cases

Subcutaneous panniculitis-like T-cell lymphoma is a rare subtype of cutaneous T-cell lymphoma. Virtually all cases are confined to the subcutaneous adipose tissue. In this report, we describe the first small series of subcutaneous panniculitis-like T-cell lymphoma (three patients) with bone marrow involvement. All patients presented with skin or soft tissue nodules, fever, and constitutional symptoms, and were diagnosed with subcutaneous panniculitis-like T-cell lymphoma based on the characteristic morphologic and immunophenotypic features of the subcutaneous lesions. Bone marrow core biopsies in these cases showed focal involvement by lymphoma with pathologic features similar to those seen in the diagnostic biopsies. Our observations suggest bone marrow involvement by subcutaneous panniculitis-like T-cell lymphoma does occur, and can be identified histologically and confirmed using standard immunohistochemistry. Our findings raise awareness of bone marrow involvement in this rare entity. However, the incidence and significance of bone marrow involvement in subcutaneous panniculitis-like T-cell lymphoma requires further evaluation.