C. Inflammatory breast cancer
The histopathological findings of the lymph node biopsy showed invasive ductal carcinoma with micropapillary features. The immunohistochemical staining was positive for GATA-3 and CK-7, along with 40% ER expression. Next-generation sequencing showed a microsatellite stable status and variations in the CDKN2, ERBB2, and PIK3CA genes. Based on these findings, the patient was diagnosed with inflammatory breast cancer (IBC) with invasive ductal carcinoma and treated with systemic chemotherapy. It is important to note that the history of receiving the COVID-19 mRNA vaccine is a red herring in this case.
It is challenging to differentiate between adnexal tumors and breast cancer when the patient presents with a cutaneous lesion of the breast. The current patient presented with a widespread rash, retracted nipple, and a peau d’orange appearance of the skin commonly seen in patients with IBC.1 However, peau d’orange skin can also be seen in patients with cellulitis and radiation-induced lymphatic blockage.2 The atypical cells obtained from a skin punch biopsy stained positive for GATA-3 and CK-7. GATA-3 belongs to the GATA family of zinc-finger transcription and is involved in the development and morphogenesis of breast tissue.3 It is commonly expressed in ER-positive breast cancers. However, the expression of GATA-3 is not exclusive to breast cancer and has been reported in tumors of the salivary gland, urothelial system, skin and adnexa, mesothelioma, and pancreas.4 Breast glands are considered to be modified and highly specialized apocrine glands. Hence, they share structural and functional homology with sweat glands.5