Frequency of HER2 Expression, MMR Deficiency, and PI3KCA Mutation in Pretreated Surgical Specimens of Patients with Esophageal Squamous Cell Carcinoma in Iran Cancer Institute.

Background & Objective: Iran is located in the esophageal cancer geographical belt. As multiple genetic alterations are responsible for the molecular pathogenesis of esophageal squamous cell cancer (ESCC), the role and frequency of HER2 expression, MMR deficiency, and PI3KCA mutation are not well defined. Methods: We carried out HER2/neu expression, dMMR/MSI high, and PI3KCA mutation analysis in specimens of patients with ESCC. We accessed archival tissue blocks related to specimens of 68 ESCC cases at the time of surgery following neoadjuvant chemoradiation. These patients underwent surgery during 2013-2018 at the Cancer Institute of Iran affiliated with the Tehran University of Medical Sciences in Tehran. Results: None of the patients showed HER2 expression, dMMR/MSI high, or PI3K mutations. Conclusion: dMMR/MSI-H and PI3KCA mutation and HER2 expression may not be reliable andfrequent targets for systemic therapy in patients with esophageal SCC.

Burned-out Post Pubertal Teratoma Presenting as a Liver Metastases in a 34-Year-Old Male.

Germ cell teratomas belong to non-seminomatous germ cell tumors and account for 95% of malignant testicular tumors. Regarding the current World Health Organization (WHO) criteria, testicular teratomas are divided into prepubertal and post-pubertal subtypes based on patients' age. The term "burned-out testicular tumor" is a very rare condition referring to a regressed testicular tumor which presents with its metastases without any clinical finding in the testicle. Metastasis can be the presentation of post-pubertal teratoma in 22-37% of cases. In scar associated teratoma (burn-out component), the metastasis rate is 66%. We reported a rare case of post-pubertal teratoma in a 34-year-old male who presented with multiple liver masses initially. Liver biopsy revealed poorly differentiated adenocarcinoma probably of gastrointestinal (GI) tract origin. The upper and lower GI endoscopy were normal. Scrotal ultrasonography showed a hypoechoic cystic intratesticular lesion in the left testis. The patient underwent radical orchiectomy and the histopathologic examination revealed post-pubertal teratoma with burned out component. The patient underwent proper treatment and is still under follow up. As a result, in a young male patient who presented with a retroperitoneal mass or poorly differentiated carcinomas of an unknown primary site, using light microscopy and immunohistochemical profiling alone may be inadequate. Therefore, scrotal screening and physical examination of the scrotum and bilateral testis should be considered to exclude possibility of a metastatic progression from a testicular germ cell neoplasia.