A Rare Presentation of Recurrent Malignant Peripheral Nerve Sheath Tumor with Glandular Differentiation-A Case Report.

Malignant peripheral nerve sheath tumors (MPNST) are rare heterogeneous group of soft tissue neoplasms. In most cases, they originate within the pre-existing neurofibromatosis. The emergence of glandular structures in MPNST is curious and enigmatic. We report a case of recurrent MPNST with glandular differentiation arising in the background of neurofibroma in a 20-year-old lady. By immunohistochemistry, MPNST showed focal positive staining for S100 and negative staining for SOX10 while adjacent neurofibroma showed diffuse positivity for S100 and SOX10. The glandular tumor cells showed positive staining for CDX2, Cam5.2, CK19, and CK7 (focal), while negative for SOX10 and S100. MPNST with glandular differentiation is quite rare which may pose a diagnostic challenge. The glandular differentiation in MPNST should be excluded from the metastasis from second primary with the aid of clinical and radiological correlation.

Malignant Gastrointestinal Neuroectodermal Tumor of Small Intestine Showing DOG1 Expression: A Case Report and Review of Literature.

Malignant gastrointestinal neuroectodermal tumor (GNET), also referred to as clear cell sarcoma-like tumor of the GI tract is a rare mesenchymal tumor of the gastrointestinal tract. It has to be distinguished from various mimickers including gastrointestinal stromal tumor (GIST) due to its aggressive course and different natural history and therapeutic approach. Here we report a case of GNET arising in the small intestine with aberrant DOG1 expression posing a diagnostic challenge. In this context, the combination of clinical, histomorphological, immunohistochemical, and molecular features helped to establish a proper diagnosis.

Langerhans Cell Hyperplasia Mimicking Langerhans Cell Histiocytosis: A Rare Complication of COVID-19 Vaccination.

Langerhans cell histiocytosis (LCH) is a rare disorder characterized by the abnormal proliferation of Langerhans cells, a type of immune cell that is normally present in the skin and various other tissues. LCH can affect people of any age but is most commonly diagnosed in children. We report a case of a patient with LCH who developed ipsilateral axillary lymphadenopathology post-COVID-19 vaccination. Lymph node biopsy showed diffuse Langerhans cell hyperplasia which mimicked LCH. Clinically and radiologically, it looked to be a reactive lymph node. The patient was kept on follow up only and after 1 year of follow up the size of lymph nodes regressed confirming to be reactive in nature rather than neoplastic. To the best of our knowledge, this is the second case of Langerhans cell hyperplasia post-COVID-19 vaccination being reported in the literature.

Signet ring cell carcinoma of the rectal stump in a known ulcerative colitis patient.

Colorectal carcinoma (CRC) is the third most commonly diagnosed cancer worldwide and is the second most common cause of cancer-related deaths. However, the Omani population shares the major burden as the most prevalent carcinoma. The disease is comparatively higher in males than females. Patients with pre-existing risk factors, including inflammatory bowel disease, are at increased risk of developing neoplasia. Among the various histopathological subtypes of adenocarcinoma in the rectum, signet ring cell carcinoma is the rarest and accounts for approximately 1% of the cases. Given the aggressive nature of this tumor, advanced presentation, stage, and poor prognosis, regular endoscopic surveillance is essential. Hereby, we report a rare case of signet ring cell carcinoma arising in the rectal stump in an already diagnosed and operated patient of Ulcerative colitis.

Signet ring cell carcinoma of the rectal stump in a known ulcerative colitis patient

ABSTRACT Colorectal carcinoma (CRC) is the third most commonly diagnosed cancer worldwide and is the second most common cause of cancer-related deaths. However, the Omani population shares the major burden as the most prevalent carcinoma. The disease is comparatively higher in males than females. Patients with pre-existing risk factors, including inflammatory bowel disease, are at increased risk of developing neoplasia. Among the various histopathological subtypes of adenocarcinoma in the rectum, signet ring cell carcinoma is the rarest and accounts for approximately 1% of the cases. Given the aggressive nature of this tumor, advanced presentation, stage, and poor prognosis, regular endoscopic surveillance is essential. Hereby, we report a rare case of signet ring cell carcinoma arising in the rectal stump in an already diagnosed and operated patient of Ulcerative colitis.

Large duodenal gastrointestinal stromal tumor presenting with acute bleeding managed by a whipple resection. A review of surgical options and the prognostic indicators of outcome.

CONTEXT: Duodenal gastrointestinal stromal tumors (GISTs) are uncommon and constitute a relatively small subset of GISTs which presents a unique dilemma having various surgical options. A case of a large ulcerating duodenal GIST arising from the second and third parts of the duodenum and involving the pancreas which was managed by a Whipple resection is presented. The literature is also reviewed to present the current status on surgical options, outcome, prognostic indicators and the role of imatinib mesylate in its management. CASE REPORT: A 58-year-old patient presented with acute gastrointestinal bleeding which was diagnosed to be due to a duodenal GIST following CT scan and endoscopic biopsy. The mass which measured about 10x9 cm originated from the 2nd part and extended into the 3rd part of the duodenum. He underwent a Whipple resection, and histopathology confirmed a duodenal GIST having a greater than 10 mitotic count per fifty high power field and areas of necrosis. Postoperatively, he received imatinib mesylate 400 mg bid; however, 4 months later, he presented with multiple disseminated peritoneal metastases and succumbed to the disease 2 months later. CONCLUSION: GISTs of the duodenum which are small in size and do not involve the papilla of Vater are better resolved using a limited resection of the duodenum since the outcome in terms of operative risk or disease recurrence is not influenced in these cases. However, large tumors with more extensive involvement would require a pancreaticoduodenectomy to achieve adequate tumor clearance. Even though duodenal GISTs have a relatively better prognosis as compared to GISTs at other sites, their aggressiveness ranges from small indolent tumors to aggressive sarcomas. Following tumor resection, a recurrence rate of about 40% has been reported. A more favorable prognosis in duodenal GISTs is attributed to a lower prevalence of P53 loss, the duodenal location of the tumor, a smaller size of the lesion and a low mitotic count. Imatinib mesylate is reported to play a role in neoadjuvant therapy as well as in the management of metastatic and recurrent disease, although some of these tumors may fail to respond.