Proximal-type epithelioid sarcoma in pubis. Case report and review of the literature.

BACKGROUND: The "proximal-type" epithelioid sarcoma (PES) is a rare variant of conventional epithelioid sarcoma. It has been described in older patients in the proximal portion of the extremities with a predilection for the pelvis and perineum. It is clinically more aggressive, showing a higher incidence of recurrence, metastasis, resistance to chemotherapy and a higher mortality. We report the case of a patient with a PES of the pubic region and we review the previous literature. CLINICAL CASE: We report the case of a 57-year-old female with a painless, progressively growing mass in the region of the pubis. We performed surgical resection of the lesion with clear margins and histological and immunohistochemical study allowed the definitive diagnosis of PES. After 4 disease-free years, the patient had a tumor recurrence at the same location. We performed en bloc resection of the lesion and immunohistochemical study confirmed the recurrence of PES. The patient refused adjuvant therapy. Today, after 4 years of follow-up, the patient remains asymptomatic and without evidence of recurrence or distant disease. CONCLUSIONS: Diagnosis of PES is complex because histological findings may be confused with multiple tumors; therefore, immunohistochemical study is definitive. PES shows positivity for epithelial markers (cytokeratin and EMA), mesenchymal markers (vimentin) as well as CD34. According to what has been reported in the literature, surgical treatment with free margins is indicated, with adjuvant therapies when the risk of recurrence is high.

Morphological characteristics of the interpubic joint (Symphysis pubica) of rats, guinea pigs and mice in different physiological situations. A comparative study.

The pubic joint of male and female rats, guinea pigs and mice was studied using the Picrosirius polarization method which selectively discloses the fibers of the collagenous system. Besides that, considerations were made regarding joint classification. In adult rats (both males and females, including intrapartum specimens), our results confirm those of earlier studies showing that the interpubic joint contains a central core of hyaline cartilage surrounded by fibrocartilaginous areas. Thus, in rats, the pubic joint should more properly be classified as a true synchondrosis. In virgin female guinea pigs and mice, the interpubic joint is formed of fibrocartilage (a true symphysis); whereas at term the bones are joined by a connective ligament, constituting a syndesmosis. Male mice have a similar (fibrocartilaginous) joint structure to virgin female mice, whereas male guinea pigs (like rats) have a hyaline cartilage joint. The foregoing observations indicate that the classification of the pubic joint depends upon the species, age, sex, and physiological reproductive stage studied. Species that are very similar in most other aspects (such as rats and mice) displayed different morphological features of the pubic joint to support the same reproductive processes. Together, the data reported here suggest that interspecies differences are likely to be found in other parameters and should be considered when choosing an appropriate animal model for research or teaching purposes.