The role of transanal total mesorectal excision in the treatment of rectal cancer: a systematic review.

INTRODUCTION: Total mesorectal excision (TME) during rectal resection is considered the gold standard for the treatment of rectal cancer. Transanal total mesorectal excision (TaTME) was first described in 2010 and has been applied to humans since 2012 to overcome some of the technical difficulties associated with minimally invasive TMEs. EVIDENCE ACQUSITION: A systematic review of the literature was conducted, and it focused on articles published between 2012 and 2022 to analyze the state of the art of surgical techniques and indications, as well as potential technical, oncological, and functional benefits. EVIDENCE SYNTHESIS: The indications for TaTME are not yet standardized, and structured training programs are necessary to complete a safe learning curve for this new technique. The procedure, when compared with conventional open or minimally invasive TME, is feasible and safe with similar intraoperative and postoperative complications. On the other hand, some new specific complications of this new approach have been described. The short-term pathological and oncologic results are encouraging, especially in terms of the mesorectal specimen quality, distal resection margin and conversion rate. Also, the functional results seem encouraging when compared with other minimally invasive techniques. CONCLUSIONS: Long-term follow-up and ongoing RCT trials are fundamental to evaluate the possible benefits in terms of local recurrence and survival. This will facilitate the comparison with other minimally invasive rectal resections.

Differential diagnosis in Rosai-Dorfman disease: A rare case of isolated hepatic presentation mimicking a metastatic tumor with positive 18-FDG uptake.

Rosai-Dorfman disease (RDD) is also called sinus histiocytosis with massive lymphadenopathy, and it is caused by a histiocytic disorder with unclear etiology. It usually involves cervical lymph nodes, but it may also present with extranodal involvement. We report a rare condition of isolated hepatic RDD without nodal involvement, clinically manifested with three-month abdominal pain and tenderness of the right hypochondrium. CT- and PET-CT scans were compatible with a secondary lesion from an unknown primary tumor. Therefore, the patient underwent an atypical liver resection. Immunohistochemistry and histological results were compatible with a diagnosis of RDD. RDD is characterized by phenomena of emperipolesis, histiocytic proliferation and positive immunostaining for CD14, CD68 and S-100 protein. Cases of isolated gastrointestinal localization of RDD are particularly rare, especially in the liver. Instrumental exams might confuse RDD with other malignancies. RDD is a rare entity, which might be misdiagnosed using PET-CT due to its similarities with malignant tumors. An accurate multidisciplinary approach may help to clear diagnostic clues of this uncommon disease.