3T-MRI, elastography, digital mammography, and FDG-PET CT findings of subcutaneous panniculitis-like T-cell lymphoma (SPTCL) of the breast.

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare subtype of cutaneous lymphoma, which is characterized by infiltration of neoplastic cytotoxic T cells into the subcutaneous tissue. We here report the case of a 66-year-old woman with SPTCL of the breast, which is a very uncommon location. Multiple suspicious irregular small masses in the subcutaneous fat were detected by mammography, and sonograms revealed hyperechoic masses. Elastography was useful to improve depiction and delineation of SPTCL in the hyperechoic subcutaneous fat, and dynamic contrast-enhanced MRI examinations showed multiple irregular rim enhanced masses with persistent enhancement. FDG-PET CT images showed hypermetabolism in areas corresponding to other imaging techniques. MRI can be useful for diagnosis of fat necrosis, which is a primary radiologic feature of SPTCL. However, fat necrosis has multitude of appearances by various imaging techniques, which typically indicate a benign disease, but may indicate a malignancy. Therefore, an ultrasonographically guided core needle biopsy is useful for a diagnosis of SPTCL of the breast. The presence of multiple subcutaneous nodules throughout the body on CT imaging may be an important finding that suggests a diagnosis of SPTCL.