RESUMO
OBJECTIVES: To study paratesticular malignant fibrous histiocytomas (FHM) from the clinical, histological, immunohistochemical and histogenetic, point of view. METHODS: Through Medline and not index-linked search of international scientific literature we have found a total of 77 cases of paratesticular FHM that globally create diagnostic, terminological and therapeutic problems. RESULTS: We include the case number 78 of FHM of spermatic cord, that presents a few special characteristics (not described before) of cutaneous fistula and infiltration of an inguinal leiomyoma, with histological and immunohistochemical confirmation. We performed a conceptual review of this type of tumours, including the evaluation of contradictions and reclassifications that has undergone from its first description, which causes that they are underestimated and their real prevalence in international series is very variable: from 7 to 37% of paratesticular sarcomas. Also, the fact of their low incidence has determined the lack of protocols for diagnosis and treatment. CONCLUSIONS: Paratesticular tumours, although infrequent, have a high rate of malignancy. The FHM concept has varied throughout the last 15 years. Today, this term is synonymous of pleomorphic undifferentiated sarcoma and has been an exclusion diagnosis (Vimentin [+]/ CD 68 [+]--occasionally--without ultrastructural differences), reserving the inflammatory subtype for which they have an inflammatory and histiocytic component. The accomplishment of an intraoperatory biopsy is essential in this location, since it is even difficult to know preoperatively, if a lesion is benign or malignant. The differential diagnosis is only solved after microscopic and inmunohistochemical study. Leiomyoma next to this location (inguinal) could be diagnosed and confused with a nodule of the main FHM. Their immunophenotype allowed us to diagnose it not only as leiomyoma (myogenic markers were positive -non skeletal muscle-), but also to observe the infiltration by the FHM.
