IntroductionBlastic plasmacytoid dendritic cell neoplasm (BPDCN) is an uncommon hematologic malignancy originating from plasmacytoid dendritic cells (1). These cells harbor a specific immunophenotype, positive for CD4 and CD56 and negative for CD3 and CD19(2). The BPDCN is classified as a separate category besides acute myeloid leukemia and B/T cell leukemia/lymphoma in the 2022 World Health Organization Classification of Hematolymphoid Tumors 5th edition (1). It commonly involves skin, and skin lesions including nodules and papules can be the only disease presentation; however, it can involve bone marrow, lymph nodes and spleen (3, 4). Leukemic reaction may also occur. Breast tissue infiltration by BPDCN has been reported in one case (4). Aggressive course and poor prognosis of the patient as well as diagnosis difficulties for pathologists and clinicians are problems that have not been resolved so far. Here we describe a case of BPDCN, someone who presented with a forehead skin lesion with focus on histopathologic diagnosis. Immunophenotyping by immunohistochemistry methods confirmed the diagnosis.

IntroductionBasal cell carcinoma is the most common primary skin neoplasm which is responsible for nearly 70% of skin malignancies(1). Different morphologic subtypes of this neoplasm have been reported in literature. Granular Basal cell carcinoma (BCC) is a very rare variant of BCC which was first reported in 1979(2). A total number of 17 cases of this subtype have been reported in literature to date. Granular cell BCC is characterized by large cells with abundant eosinophilic and granular cytoplasm and eccentrically located nucleus.Metatypical BCC is another rare subtype of BCC, composed of nests and cords of cells with peripheral palisading and cleft formation between tumor nests and adjacent stroma (indicative feature of BCC) with variable squamous maturation (1). keratinization is rare(3), which helps differentiate from squamous cell carcinoma. Large cells with increased amount of eosinophilic cytoplasm are also present(1). This subtype of BCC is rare and only limited data is submitted to literature. Granular cell change can also occur in other neoplasms. In cases without areas of conventional BCC, a definite diagnosis would be difficult or misdiagnosis would be made. Rather than that, some BCCs lack clefting or epidermal attachment, so pathologists ought to be familiar with this subtype of BCC for appropriate diagnosis.In this study we are about to present a case of BCC with both metatypical and granular cell change.