Heterotopic pancreas is a rare congenital abnormality. The most common location is the stomach, duodenum and proximal jejunum. Rare locations are represented by the ampulla of Vater, esophagus, ileum, Meckel diverticulum, biliary tract, mesentery and spleen. We present the case of a 49 year old patient investigated for obstructive jaundice and diagnosed with an ampullar heterotopy of pancreas parenchyma, initially considered to be a malignant tumor. A Whipple pancreatoduodenectomy was performed with good postoperative evolution, the serum levels of bilirubin being normal after the first postoperative week.

The thymus derives from the third branchial pouch, which migrates to the mediastinum through the central region of the neck. During the migration, particles split off and develop separately. The prevalence of ectopic thymus is 20-40%. The purpose of this retrospective case series study was to investigate the prevalence of embryological tissue remnants in the central region, in patients treated for thyroid lesions. Between January 1 2018 and September 1 2020, 84 patients who underwent central neck dissection were selected. Clinicopathological data as age, gender, histopathological result and TNM stage were analyzed. Ectopic tissue in the central neck region was discovered in 28 cases. The prevalence of ectopic lesions showed increase in Stage I thyroid carcinomas. There was no significant correlation with patients\' age, gender, or with the stage. We emphasize the clinicopathological role of ectopic tissues, which can occur in the central region of the neck.

The study aims to summarize the clinical characteristics of patients with ectopic gastric mucosa in the small intestine, comparing clinical presentation differences between domestic and foreign patients through literature review. The clinical characteristics of cases diagnosed with ectopic gastric mucosa in the small intestine at Peking Union Medical College Hospital from January 2000 to January 2024 were retrospectively analyzed. By searching databanks, such as PubMed, EMBASE, the Cochrane Library, Wanfang, VIP, CNKI, and etc (the inclusion period was from the establishment of the database to January 1, 2024). The literature review was conducted on ectopic gastric mucosa in the small intestine. A total of 10 cases were included, all male, age [M (Q1, Q3)] was 27 (13-69) years old. Gastrointestinal bleeding was the first manifestation in most cases, with severe cases leading to hemorrhagic shock. Abdominal CT indicated local intestinal wall thickening and luminal narrowing in 3 cases. Four cases lesions were located at the beginning of the jejunum and 6 lesions were located in the end segment of ileum. All cases underwent local lesion resection, with postoperative pathology confirming ectopic gastric mucosa. Symptoms disappeared postoperatively, with a follow-up period of 0.5-3.0 years. Literature review indicates that the main clinical manifestation of gastric mucosa ectopia in the small intestine in China is gastrointestinal bleeding, while foreign patients are often complicated with intestinal duplication and intussusception, with abdominal pain and vomiting as the primary and main symptoms. The occurrence rate of intestinal obstruction in female patients, both domestically and abroad, is higher than that in male patients. The occurrence rate of ileal lesions with intestinal obstruction and small intestinal duplication is higher than that of duodenal lesions in both domestic and foreign patients. Local small intestine resection is an effective treatment method with generally good prognosis. Ectopic small intestinal mucosa is relatively rare, with symptoms of gastrointestinal bleeding and intestinal obstruction being common presentations, which can serve as one of the differential diagnoses for unexplained gastrointestinal bleeding.
总结小肠胃黏膜异位患者的临床表现，并通过文献复习比较国内外患者的临床表现差异。回顾性分析北京协和医院自2000年1月至2024年1月确诊为小肠胃黏膜异位的病例的临床特征。通过检索Pubmed、EMBASE、the Cochrane Library、万方、维普、知网等数据库；纳入时间为自数据库建库至2024年1月1日，对小肠胃黏膜异位进行文献复习。共纳入10例患者，均为男性，年龄［M（Q1，Q3）］为27（13~69）岁。病例多以消化道出血为首发表现，严重者出现失血性休克。腹部CT提示3例患者局部小肠壁增厚及肠腔狭窄。4例病变位于空肠起始段，6例位于回肠末段。所有病例均接受了局部病变切除术，术后病理证实为小肠胃黏膜异位。术后所有患者症状均消失，随访时间为0.5~3.0年。文献复习提示我国小肠胃黏膜异位临床主要表现为消化道出血；而国外患者多合并肠道重复畸形，并引发肠套叠，临床多以腹痛、呕吐为首发及主要表现。国内外女性患者肠梗阻发生率均高于男性；国内外患者回肠病变肠梗阻及合并小肠重复畸形的发生率高于空肠病变。局部小肠切除术是有效治疗方式，多预后良好。小肠胃黏膜异位较为罕见，消化道出血及肠梗阻症状为常见表现，可作为不明原因消化道出血的鉴别病因之一。.

When a neuroendocrine tumor with abundant blood flow is located in the pancreatic tail, it is difficult to distinguish it from accessory spleen. The patient was a 71-year-old woman who was admitted with impaired consciousness and hypoglycemia, raising suspicion of insulinoma. The selective arterial calcium injection test suggested a lesion in the pancreatic tail. Contrast-enhanced computed tomography and magnetic resonance imaging (MRI) showed a mass in the splenic hilum; however, its continuity with the pancreas was unclear. Contrast-enhanced MRI using super paramagnetic iron oxide (SPIO) showed no SPIO uptake in the splenic hilar mass. SPIO contrast-enhanced MRI is considered useful for differentiating pancreatic endocrine tumors from paraspleen tumors.

BACKGROUND: Choristoma is a well-defined benign lesion formed by histologically normal tissue in an unusual location. Diagnosis is confirmed after surgical removal of the mass. To our knowledge, to date there has been only one case of thyroid choristoma described in the literature.
METHODS: A 70-year-old man with a history of non-Hodgkin lymphoma presented with sudden cervical enlargement. Cervical CT scan showed a 47mm hypodense nodule on the right thyroid lobe. Fine-needle aspiration revealed follicular lesion of undetermined significance. During the following weeks there was noticeable thyroid enlargement. Reassessment with thyroid ultrasound showed a 73mm nodule. The patient underwent total thyroidectomy. Histopathological examination revealed a choristoma composed of squamous epithelium lined cysts, smooth muscle, adipose tissue, connective tissue, foci of ossification and extramedullary hematopoiesis. No cytological atypia or tumoral necrosis were found. Thyroid choristomas are an exceedingly rare cause of a thyroid nodule.

Microscopic heterotopic extraovarian sex cord-stromal proliferations were first reported in the literature in 2015 by McCluggege. Afterwards, few similar cases have been described. Herein, we report the fourteenth case of microscopic heterotopic sex cord-stromal proliferation and the third case sited in the pelvic peritoneum. The clinical history of these rare cases suggests their benign nature. Knowledge of this histological pattern is important for differential diagnoses such as malignant pathologies and metastatic diseases.

Choristomas are proliferative growths that occur when normal tissue develops in abnormal locations and may resemble tumors. Oral choristomas commonly present as slow-growing, indolent, and firm masses. The diagnosis primarily relies on histopathologic examination. Given their tumor-like growth and developmental pathogenesis, it is critical to differentiate them from neoplasms. In this article, we present two clinical cases of oral choristomas, a cartilaginous choristoma, and an osseous choristoma of the tongue. We also offer a brief review of the literature discussing clinical presentation, microscopic features, and therapeutic options.

A primary orbital respiratory cyst is a congenital choristoma that presents in the orbit and with different signs and symptoms depending on the location, which might also change the surgical approach. The aim of this report is to describe 2 new cases of primary respiratory epithelial cysts and to review the literature on presentation, management, and risk factors with different surgical approaches and complications. Two cases presenting with gradually increased proptosis had a confirmed diagnosis of a respiratory epithelial cyst. CT and MRI imaging revealed a thin-walled intraconal cystic lesion. Complete surgical removal was not possible and an incisional biopsy of the wall was performed. Rarely, orbital respiratory epithelium cysts are primary lesions. The high risk of breaking the capsule during surgery and the presence of residual epithelial cells within the orbit may cause cyst\'s recurrence. Indeed, we recommend careful attention during dissection maneuvers and a long-term follow-up.

UNASSIGNED: Osseous choristoma is a rare entity, mainly found on the posterior tongue. It is described as a nodular or exophytic lesion with firm to hard consistency. Clinicians should consider osseous choristoma when confronting lesions with the same features.
UNASSIGNED: Osseous choristoma is an unusual growth of ectopic bone in the soft tissue. This lesion is extremely rare, with a few cases reported in the literature, and they typically appear in the head and neck region, particularly the posterior tongue. The current report presents a case of osseous choristoma in the palate of a 51-year-old female. The patient had slight discomfort, which was resolved after surgical excision of the lesion, and no recurrence was observed. This research presents an instance of osseous choristoma in a less common location and concurrently acts as a review of this rare condition.

OBJECTIVE: Cervical chondrocutaneous branchial remnants (CCBRs) and dermal lesions, such as epidermoid cysts or brachial anomalies, including lateral cervical cysts/sinuses or dermal sinuses of anterior chest lesions, are usually located at the lower neck at the anterior or posterior border of the sternocleidomastoid muscle (SCM). We aimed to demonstrate the usefulness of ultrasonography in the differential diagnosis and evaluation of CCBRs.
METHODS: We evaluated 22 lesions of 20 pediatric patients, classified into CCBR and dermal lesion groups. We used Fisher\'s exact test to evaluate differences between these groups in terms of lesion shape (low-echoic mass- or tubular-like), whether the lesion was adjacent to/in contact with the SCM or not, and the presence or absence of a concave SCM caused by the lesion.
RESULTS: Of the 22 lesions, 8 were CCBRs, and 14 were dermal lesions. We found a significant difference in the presence/absence of adjacency to or contact with the SCM (presence/absence of adjacency to or contact with the SCM in CCBRs vs that in dermal lesions: 6/2 vs 1/13, P = .002) and presence/absence of lesion-induced concavity of the SCM (presence/absence of lesion-induced concavity of the SCM in CCBRs vs that in dermal lesions: 3/5 vs 0/14, P = .036). The lesion shape (low-echoic mass-like/tubular-like lesions) did not significantly differ between the two study groups (low-echoic mass-like/tubular-like lesions in CCBRs vs that in dermal lesions: 5/3 vs 11/6, P = .624).
CONCLUSIONS: CCBRs have a strong association with the SCM. These sonographic findings may be useful in the differential diagnosis of dermal cervical lesions.