Infected Mature Teratoma in the Anterior Mediastinum Removed Using the Da Vinci Robotic System.

Mature teratomas have been found to be the most common type of extragonadal primary germ cell tumors found in the anterior mediastinum. Over the past decade, several reports have been published using minimally invasive approaches to remove mediastinal masses. Of these publications, only one reported a teratoma excision from the anterior mediastinum via the Da Vinci Robot. Additionally, there have been few reports regarding teratomas infected with bacteria. This is a case of a 37-year-old man with an incidentally identified Proteus mirabilis infected mature teratoma in the anterior mediastinum that was removed with the Da Vinci Robotic System.

Transformation of a Benign-Appearing Fibroepithelial Lesion to a Giant Malignant Phyllodes Tumor of the Breast.

This is a case of a woman who presented with a left breast mass that was initially diagnosed as fibroadenoma on core biopsy and, after three years without any surgical intervention, was found to be a malignant phyllodes tumor. Initially, a core needle biopsy of the mass showed probable fibroadenoma. Because of the initial benign seeming diagnosis and the need to treat her tongue cancer, the patient did not recognize the need for a recommended surgical consultation and excision. Three years later, she presented after the mass had enlarged to encompass nearly the whole left breast. Core needle biopsy revealed spindle cell proliferation with scattered benign-looking tubules. Due to the large size of the mass, she underwent a total mastectomy, and the final pathology demonstrated a malignant phyllodes tumor. This case demonstrates a case of progression of a benign-appearing fibroepithelial lesion to a malignant phyllodes tumor three years later.

Dorsomedial hypothalamic lesions block Syrian hamster testicular regression in short day lengths without diminishing increased testosterone negative-feedback sensitivity.

The dorsomedial nucleus (DMN) of the hypothalamus, the only site within the mediobasal hypothalamus of Syrian hamsters that both binds melatonin and has abundant concentrations of androgen receptors, has been proposed as a target tissue for induction of seasonal changes in brain sensitivity to steroid negative feedback. We tested whether DMN ablation, which does not interfere with pineal gland secretion of melatonin in short day lengths, prevents testicular regression by altering sensitivity to steroid negative feedback. Hamsters with DMN lesions, unlike control hamsters, failed to undergo testicular regression after transfer from a long (14 h light/day) to a short day length (8 h light/day); however, increased negative-feedback inhibition of follicle-stimulating hormone by testosterone was not compromised by ablation of the DMN, indicating that this tissue is not an essential mediator of seasonal changes in feedback sensitivity. We propose a redundant neural network comprised of multiple structures, each of which contributes to neuroendocrine mechanisms, that determines the effect of short days on gonadal function.