Subcutaneous Panniculitis-Like T-Cell Lymphoma in Children: Two Case Reports

Abstract

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare primary cutaneous lymphoma derived from cytotoxic αβ T cells, clinically and histopathologically resembling inflammatory diseases of adipose tissue, particularly lupus panniculitis. It accounts for <1% of all non-Hodgkin's lymphomas, with approximately 20% of cases occurring in children. The main aim of this paper was to present two pediatric cases of SPTCL, highlighting the diagnostic challenges involved. The first patient, a 5-year-9-month-old boy, was admitted with a 15 cm infiltrative lesion on the left thigh, previously misdiagnosed and unsuccessfully treated with antibiotics. Imaging revealed an infiltrate resembling lymphedema. A biopsy confirmed SPTCL with a typical immunophenotype. The patient received EURO-LB 02 protocol therapy for peripheral T-cell lymphoma, complicated by pancytopenia, respiratory infection, and polyneuropathy. Post-treatment follow-up showed lesion regression, with residual subcutaneous atrophy (5 cm). The second patient, a 7-year-old girl, presented with a 10 cm inflammatory lesion on the left thigh and systemic symptoms. Imaging and histopathology confirmed the diagnosis. She was treated with the same protocol. Three years later, disease recurrence occurred on the left forearm, managed with alemtuzumab and methotrexate. Both patients remain under outpatient follow-up. Despite its rarity, SPTCL poses a significant diagnostic challenge in children. Accurate differentiation and early diagnosis are crucial for prompt and effective treatment.

Keywords: children; differential diagnosis; pediatric; skin diseases; subcutaneous panniculitis-like T-cell lymphoma.

Figure 1

Clinical evolution of the SPTCL lesion on the left thigh: (A) before treatment, (B) after steroid therapy induction.

Figure 2

MRI image of the SPTCL lesion of the left thigh before treatment. Infiltrates with lymphoedema morphology, with a diffuse area of reduced signal intensity (60 x 20×70 mm), most likely corresponding to a neoplastic infiltrate. The lesion was measured and marked with a white indicator in the figure.

Figure 3

A follow-up MRI showing regression of the primary lesion in one month after the start of therapy. Significant regression of the described lesions of the subcutaneous tissue (24 x 7×60 mm), the nature of residual edema of the subcutaneous tissue. The lesion was measured and marked with a white indicator in the figure.

Figure 4

A follow-up MRI in six months after the start of the therapy. In the proximal part of the left femur: oval focal lesion (18 x 17×55 mm), surrounded by a thin sclerotic rim - a picture of bone infarction. The lesion is marked with a white indicator.

Figure 5

Clinical image of the skin lesion in the patient immediately after the biopsy.

Figure 6

Histopathological image (H+E staining) of a skin biopsy taken from the patient. Lesion showing SPTCL lymphoma with a typical arrangement of lymphocytes surrounding adipocytes (known as rimming).