Leiomyosarcoma mimicking acute appendicitis: a cautionary tale!

Appendiceal neoplasms are rare, occurring in <1.4% of all appendicectomy specimens. Carcinoid tumours and adenocarcinomas comprise the majority of cases, however, lymphomas or sarcomas may also arise within the appendix. Appendiceal leiomyosarcomas are rare and to date, there remains a relative dearth of cases reported in the literature. Leiomyosarcomas are derived from the smooth muscle cells or mesenchymal stem cells committed to this line of differentiation. However, their pathogenesis and underlying genetic mechanism remains to be fully elucidated. Unbalanced karyotypic defects are the only shared features observed across different leiomyosarcoma subtypes. Children with AIDS have a higher incidence compared with adults, where the main pathology in individuals with HIV is Kaposi's sarcoma and B-cell lymphoma. Although surgical excision with clear margins remains the treatment of choice, a good response to treatment with gemcitabine, docetaxel and trabectedin has been observed. The authors present the case of a 23-year-old female presenting to the emergency department with acute appendicitis. She underwent a laparoscopic converted to an open appendectomy. Her operation was complicated by a pelvic collection requiring percutaneous drainage and an ileus. Histopathological examination confirmed the diagnosis of a leiomyosarcoma, a rare mesenchymal tumour presenting in individuals with immune suppression. HIV serology was positive and she commenced anti-retroviral therapy. She remains under review in the Department of HIV Medicine.