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Developmental cysts are very rare lesions occurring in the retrorectal space, and include epidermoid, dermoid, tailgut cysts and teratomas. There is little information on their natural history and biologic behavior, although a recent paper reported a greater incidence of malignant transformation than previously thought. The diagnosis requires high-resolution imaging, and complete surgical excision is the treatment of choice. In this paper we analyzed short- and long-term results of surgical excision of six retrorectal developmental cysts observed at our institution over a period of 11 years. All patients were women, three were referred with an infected perineal fistula/pelvic abscess after having undergone drainage surgery elsewhere. In these three patients, excision was attempted through a trans-perineal approach, which was technically demanding and ultimately incomplete because of the intense surrounding inflammation. Multiple re-interventions were required for tumor recurrence, and two of them still present an occasional perineal discharge. In the other three patients, a trans-perineal or trans-anal route was employed according to tumor location, without any recurrence at a median follow-up of 118.5 months. Final pathologic diagnosis included five tailgut cysts and one teratoma. This paper shows that the treatment of developmental cysts may be very challenging, especially when they are associated with a concomitant fistula/abscess and are not correctly diagnosed at presentation. In our experience, healing was finally achieved in four patients out of six. All the lesions were benign, and no malignant transformation was observed during follow-up, even in tumors partially resected.

The purpose of this study was to show a gradient of possible bilateral activation for movements of the non-dominant vs. dominant hand, as well as for areas involved in complex vs. simple hand movements. A standard 1.5 T magnetic resonance imaging (MRI) system has been utilized to localize the cortical motor hand areas, using the blood oxygen level dependent contrast (BOLDc) technique and single-section fast low-angle shot (FLASH) imaging. Ten normal right-handed subjects volunteered for the study. The motor tasks consisted of simple (flexion-extension) finger movements of either hand, and complex movements (finger-to-thumb opposition in a repeating, pre-planned sequence) of the non-dominant hand. Simple movements caused contralateral activation of the primary motor area (MA); ipsilateral activation was observed for the non-dominant hand only. Supplementary motor area (SMA) was also activated, with a clear contralateral prevalence. The ratio of bilateral activation of MA did not change with complex movements of the non-dominant hand, while SMA as well as lateral premotor area were largely bilaterally activated in this task. In conclusion, the ipsilateral MA is activated for movements--even simple--performed with the non-dominant hand. There is widespread functional activity, involving both contralateral and ipsilateral SMA, for complex movements.