Histologic examination showed a diffuse infiltrate of large, atypical lymphoid cells intermingled with neutrophils and eosinophils throughout the dermis and in the subcutis (Figure 2 [hematoxylin-eosin, original magnification ×25]). The tumor cells were large and showed vesicular, pleomorphic (roundish, polylobate, or horseshoe-shaped) nuclei; prominent nucleoli; and slightly basophilic cytoplasm (Figure 3 [hematoxylin-eosin, original magnification ×400]). There was no epidermotropism. Immunohistochemical staining showed diffuse, strong positivity for CD30 and negativity for anaplastic lymphoma kinase protein (ALK). Anti–Ki-67 MIB1 antibody labeled approximately 90% of tumor cells, revealing a high proliferative index. Epstein-Barr virus–latent membrane protein and Epstein-Barr virus–specific RNA were not detected. Polymerase chain reaction analysis of T-cell receptors showed monoclonal rearrangement of β and γ genes. A blood chemistry profile and other studies (computed tomography of the chest and abdomen, bone scans, and bone marrow biopsy) revealed no abnormalities. The patient was treated with wide local excision and had no evidence of recurrence after 13 months of follow-up.
A Nodule on a Boy’s Back—Diagnosis. Arch Dermatol. 2007;143(3):417-422. doi:10.1001/archderm.143.3.417-e