Subcutaneous panniculitis-like T-cell lymphoma presenting with clinicopathologic features of dermatomyositis

Coexistence of Subcutaneous Panniculitis-Like T-Cell Lymphoma and Dermatomyositis in a 12-Year-Old Boy

Subcutaneous panniculitis-like T-cell lymphoma (SPTL) is an extremely rare, indolent skin malignancy that can be difficult to distinguish from autoimmune disease-associated panniculitides. Here, we describe a 12-year-old boy who was diagnosed at age 7 years with dermatomyositis with classical manifestations, including poikiloderma, Gottron's sign, and symmetric muscle weakness. Recently, the boy presented multiple subcutaneous nodules and fever. Histopathological examination and immunohistochemical staining revealed coexistence of SPTL. To our knowledge, this is the first case of dermatomyositis accompanied with SPTL. This case alert clinical physicians of the possibility of SPTL should be considered when a patient with dermatomyositis has new lesions presenting as nodules and unknown fever.

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.

Inflammatory myopathies and lymphoma

The inflammatory myopathies comprise a group of immune-mediated muscle diseases. Lymphoma is a term for a variety of lymphatic system malignancies. Autoimmune diseases and lymphoproliferative malignancies share a complex bidirectional relationship. A causal relationship between inflammatory mypathies and lymphoma has not been established. The diagnosis/treatment of inflammatory myopathy usually precedes the detection/diagnosis of lymphoma. Immune system dysregulation presumably underlies the evolution of lymphoma in patients with inflammatory myopathies. Inflammatory activity with chronic B-cell activation and/or antigen stimulation is deemed the major risk factor for lymphoma in patients with autoimmunity. A "paraneoplastic" phenomenon or the effects of immunosuppressive therapy may be alternative immune-based mechanisms. In chronic lymphocytic leukemia immune system disturbance rarely results in non-hematological autoimmune disease, including inflammatory myopathies.