INFLAMMATORY MYXOHYALINE TUMOR OF DISTAL EXTREMITIES WITH VIROCYTE ORREED-STERNBERG-LIKE CELLS - A DISTINCTIVE LESION WITH FEATURES SIMULATING INFLAMMATORY CONDITIONS, HODGKINS-DISEASE, AND VARIOUS SARCOMAS

We report 51 cases of a previously undescribed tumor of the distal ext remities that is often mistaken for an inflammatory os' infectious pro cess, Hodgkin's disease, or various sarcomas. These lesions developed in patients of all ages (range, 4-81 yr; median, 40 yr) and affected t he sexes nearly equally (27 men, 24 women). They presented as a painle ss mass of the fingers (14 cases), hand (11 cases), wrist or arm (10 c ases), toe or foot (8 cases), or lower leg (5 cases), usually within t he subcutaneous tissues. Grossly, they were infiltrative, multinodular masses characterized by a dense chronic inflammatory infiltrate that merged with a stroma, which varied from densely hyaline to focally myx oid and contained sheets of short spindled to rounded epithelioid cell s. Focally, the epithelioid cells were extremely large with bizarre, v esicular nuclei and macronucleoli resembling Reed-Sternberg cells or v irocytes. Despite the level of atypia, mitotic activity was low. The t umor cells consistently expressed vimentin but lacked a variety of oth er mesenchymal, epithelial markers, e.g., S100 protein, desmin, actin, neuron-specific endolase, epithelial membrane antigen, HMB-45, CD34) and leukocyte markers (CD15, CD30, CD45). Keratin was noted focally an d weakly in four cases and. CD68 focally in six cases, the latter sugg esting that the cells had acquired phagocytic properties. Immunostains for cytomegalovirus were negative. Polymerase chain reaction for Epst ein-Barr virus showed amplification levels consistent with latent infe ction in 4 of 10 cases, but no cases showed levels consistent with act ive infection. All of the bacterial and viral cultures were negative. Follow-up information was available in 27 cases. Recurrences developed in six patients (interval, 15 mo - 10 yr), but there were no metastas es or tumor-related deaths. In one patient, progressive proximal exten sion up the arm was noted. Although the most common submitting diagnos is was that of an inflammatory or infectious process, the negative stu dies for infectious agents, clinical behavior with local recurrences, immunophenotypic profile, and cytologic atypia support the idea that t hese are unusual mesenchymal neoplasms with at least the potential for local recurrence. It remains to be investigated whether with time the se lesions will prove to have metastatic potential.