case_images: PMC11830503_01
case_images: Photo of the recurrent BCC on the left preauricular area and medial helical rim of the pinna. BCC: basal cell carcinoma.
case_images: cureus-0017-00000077583-i01.jpg
case_images: PMC11830503_01_cureus-0017-00000077583-i01.jpg
case_images: FIG1
case_images: Frozen section from stage I of the Mohs excision showing morphoeic BCC (arrow) with dense lymphoid infiltrate (H&E x40 magnification) later confirmed as lymphoma. BCC: basal cell carcinoma.
case_images: cureus-0017-00000077583-i02.jpg
case_images: PMC11830503_01_cureus-0017-00000077583-i02.jpg
case_images: FIG2
case_images: The first stage showed morphoeic BCC at all levels of all blocks (Figure 2). 
case_images: Persistent widespread lymphocytic inflammation seen on frozen sections from stage II Mohs excision (H&E x40 magnification)
case_images: cureus-0017-00000077583-i03.jpg
case_images: PMC11830503_01_cureus-0017-00000077583-i03.jpg
case_images: FIG3
case_images: This infiltrate consisted of a mixture of centrocytes (small germinal center B lymphocytes with cleaved nuclei) and larger centroblasts (activated germinal center B lymphocytes with large vesicular nuclei and 2-3 nucleoli adjacent to the nuclear membrane), raising suspicion of possible lymphoma (Figure 3).
case_images: Immunohistochemistry showing positive CD20 immunostaining highlighting the B-cell lineage of lymphocytes (3,3'-diaminobenzidine (DAB) x40 magnification)
case_images: cureus-0017-00000077583-i04.jpg
case_images: PMC11830503_01_cureus-0017-00000077583-i04.jpg
case_images: FIG4
case_images: The neoplastic cells were strongly positive for B-cell markers (CD20 and CD79a) (Figure 4) and germinal center markers (CD10, BCL2, and BCL6), while negative for cyclin D1.