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.

BACKGROUND: Heterotopic gastric mucosa (HGM) can be located in various parts of the gastrointestinal tract. As a rare anomaly in the small intestine, it can become complicated by intussusception, obstruction, gastrointestinal bleeding, and even peritonitis, leading to death.
METHODS: This case report focuses on a 12-year-old Middle Eastern boy who presented with hematochezia and abdominal pain for a couple of days. A tagged Red blood cell (RBC) scan and Technetium scan revealed gastrointestinal bleeding at the lower abdomen, highly suggestive of the diagnosis of Meckel\'s diverticulum. Subsequently, exploratory laparotomy revealed contiguous and scattered mucosal lesions with multiple polyps of various sizes in the terminal ileum. Meckel\'s diverticulum was absent, and the patient was treated with resection and primary anastomosis. The resected tissue revealed extensive ectopic gastric mucosa and polypoid tissues. The patient recovered uneventfully and was discharged four days after the surgery. The symptoms did not recur within six months after his surgery.
CONCLUSIONS: Our case demonstrated that despite the rarity of multiple polypoid gastric heterotopias in the terminal ileum, it should be considered as one of the differential diagnoses of gastrointestinal tract bleeding.

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 gradually progressive solitary cystic-solid mass of chest CT scans is highly suggestive of lung cancer. We report a case of a 29-year-old woman with a persistent cystic-solid lesion in the right upper lobe. A chest CT scan showed a 35 mm × 44 mm × 51 mm focal cystic-solid mass in the anterior segment of the right upper lobe. The size of lesion had increased over 3 years, especially for the solid component. The right upper lobe pneumonectomy was performed. Postoperative pathological examination showed placental transmogrification of the lung, which is a rare cause of pulmonary cystic lesion.

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.

BACKGROUND: Ectopic cervical thymoma (ECT) is an extremely rare tumor, especially in association with myasthenia gravis (MG).
METHODS: We report a case of myasthenia gravis with an ectopic thymoma in the neck, whose myasthenic symptoms significantly improved after complete removal of the mass. A 55-year-old woman with generalized myasthenia gravis (MG) experienced worsening neuromuscular weakness after abruptly discontinuing pyridostigmine. Testing revealed acetylcholine receptor-antibody (AChR-Ab) positivity and a cervical mass initially thought to be thyroid or parathyroid was identified as a thymoma, type A. Post-surgery and radiation therapy, her myasthenic symptoms improved significantly with less prednisone and pyridostigmine requirements over time and no need for additional immunotherapies.
CONCLUSIONS: Diagnosing ECTs is challenging due to rarity, atypical locations, and inconclusive fine needle aspiration cytology (FNAC) results, often misinterpreted as thyroid or parathyroid lesions. As proper management of patients with MG, including thymectomy, offers favorable clinical outcomes such as significant improvement in myasthenic complaints and reduced immunosuppressive medication requirements, clinicians should be vigilant of the ectopic locations of thymomas to ensure timely diagnosis and intervention.

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.

UNASSIGNED: Epibulbar choristoma is a benign congenital lesion containing histologically normal-appearing tissue in an abnormal ectopic location. An epibulbar choristoma is classified as either epibulbar dermoid, dermolipoma, or complex choristoma based on histological examination. The case presented was a presumed epibulbar dermolipoma with no signs of ossification on imaging, examination, or intraoperatively until the specimen was examined histologically, clarifying the lesion as an epibulbar complex choristoma. Reassuringly, the presence of bone in such lesions should not change management.
UNASSIGNED: A mother noticed a small fleshy mass on her 9-year-old daughter\'s superotemporal bulbar conjunctiva. The suspected epibulbar dermolipoma was confirmed with MRI and initially managed conservatively. Two years later, she was referred for apparent growth and cosmetic concerns, and she underwent surgical debulking.
UNASSIGNED: We present this case for its unusual presentation and histological findings. Orbital surgeons should be aware of the possibility of ossification of epibulbar choristomas and avoid confusion with alternative diagnoses. Clarification of the latest classification system for epibulbar choristomas is provided.

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.