Anal leiomyosarcoma: A case report and review of literature.

INTRODUCTION: Leiomyosarcoma is a malignant neoplasm that is derived from smooth muscle cells in walls of small blood vessels or branch of the inferior vena cava, the uterus and the gastrointestinal tract. Different treatment options are present for the treatment of LMS. However, due to the rarity of LMS, the optimal treatment option is still to be discussed and determined. PRESENTATION OF CASE: A 51-year-old male patient, previously healthy, presented for perianal pain. Biopsy of the mass found showed spindle cell tumors with mild atypia, dense cellularity, and pelvic MRI with contrast showed a well-circumscribed mass of the anus, developed between the layers of the external sphincter with possible invasion of the internal sphincter consistent with Leiomyosarcoma Grade I. Wide excision was performed. Close follow-up should be done every 3 to 6 months for the first 2 to 3 years, every 6 to 12 months for the following 3 years, and annually afterwards. DISCUSSION: The symptoms of LMS include rectal bleeding with rectal and/or abdominal pain, weight loss, constipation, altered bowel motion and protruding mass. Treatment options include wide local excision, abdominoperineal resection, low anterior resection, bloc resection and pelvic exenteration. Patients who underwent wide local excision show a higher local recurrence rate as compared to patients who underwent radical resection. Distant metastasis is higher in patients who underwent radical resection. CONCLUSION: The treatment options of anal LMS are controversial. At present, very few cases have been reported, thus no universally accepted standard of surgical treatment has been established.

Membrane Targeting and GTPase Activity of Rab7 Are Required for Its Ubiquitination by RNF167.

Rab7 is a GTPase that controls late endosome and lysosome trafficking. Recent studies have demonstrated that Rab7 is ubiquitinated, a post-translational modification mediated by an enzymatic cascade. To date, only one ubiquitin E3 ligase and one deubiquitinase have been identified in regulating Rab7 ubiquitination. Here, we report that RNF167, a transmembrane endolysosomal ubiquitin ligase, can ubiquitinate Rab7. Using immunoprecipitation and in vitro ubiquitination assays, we demonstrate that Rab7 is a direct substrate of RNF167. Subcellular fractionation indicates that RNF167 activity maintains Rab7's membrane localization. Epifluorescence microscopy in HeLa cells shows that Rab7-positive vesicles are larger under conditions enabling Rab7 ubiquitination by RNF167. Characterization of its ubiquitination reveals that Rab7 must be in its GTP-bound active form for membrane anchoring and, thus, accessible for RNF167-mediated ubiquitin attachment. Cellular distribution analyses of lysosome marker Lamp1 show that vesicle positioning is independent of Rab7 and RNF167 expression and that Rab7 endosomal localization is not affected by RNF167 knockdown. However, both Rab7 and RNF167 depletion affect each other's lysosomal localization. Finally, this study demonstrates that the RNF167-mediated ubiquitination of Rab7 GTPase is impaired by variants of Charcot-Marie-Tooth Type 2B disease. This study identified RNF167 as a new ubiquitin ligase for Rab7 while expanding our knowledge of the mechanisms underlying the ubiquitination of Rab7.

Malignant carcinoma and skin melanoma neoplasms concomitantly in the thyroid.

Malignant melanomas metastatic to the thyroid gland are uncommon. Based on microscopy and DNA methylation profile, we report a rare coexistence of neoplasms in the thyroid, presumably in our case, with relapse-free condition on adjuvant therapy.

Solitary intestinal neurofibroma with no associated systemic syndromes causing intussusception: Case report and literature review.

INTRODUCTION: The isolated presence of neurofibromatous lesions in the gastrointestinal tract, with no associated systemic syndromes, is a rarely reported clinical entity. PRESENTATION OF CASE: A 48-year-old lady, with no history of neurofibromatosis or other systemic disease, presented with small bowel obstruction secondary to an ileo-ileal intussusception induced by an isolated ileal neurofibromatous mass. The patient underwent a segmental enterectomy and after a smooth recovery, she was put on a long-term follow-up schedule. DISCUSSION: This article presents a review of the literature of this area clinical entity. Very few reports of gastrointestinal isolated neurofibromas could be found. Similarly, extra-digestive isolated lesions have been rarely reported. CONCLUSION: Isolated ileal neurofibroma is a rare pathological entity. The clinical significance of such a diagnosis lies mainly in the need of further follow up of these patients as the bowel involvement could be the first manifestation of neurofibromatosis type 1 or multiple endocrine neoplasia type 2b.

Duodenal duplication cyst in a 52-year-old man: A challenging diagnosis and management.

INTRODUCTION: Duodenal duplication is a rare congenital malformation. Although more frequent in childhood, it may rarely be observed in adulthood. Pre-operative diagnosis can be difficult. PRESENTATION OF CASE: We report the case of a 52-year-old man with a duodenal duplication cyst, who was misdiagnosed even after a primary surgery. Definitive treatment needed an extensive diagnostic workup and a second delicate operation. DISCUSSION: This article discusses the incidence of duodenal duplications, their types, their clinical presentations, the radiologic and diagnostic features along with different therapeutic options. CONCLUSION: Duodenal duplication should always be one of the differential diagnoses proposed when approaching upper abdominal cystic formations.