No abstract

Sclerosing extramedullary hematopoietic tumor (SEMHT) is a rare tumor that can occur in association with some chronic myeloproliferative neoplasms, particularly myelofibrosis. The morphology of SEMHT can mimic that of a wide variety of other lesions, both macroscopically and microscopically. SEMHT originating from the colon is extremely rare. The present study reports a case of SEMHT in the colon with involvement of the peri-intestinal lymph nodes. On the basis of the clinical symptoms and endoscopic results, a malignant tumor of colon was suspected. Pathological examination revealed the deposition of collagen and hematopoietic components in the fibrous mucus background. Immunohistochemical staining for CD61 confirmed the presence of atypical megakaryocytes, while immunohistochemical staining for myeloperoxidase and glycophorin A highlighted the existence of granulocyte and erythrocyte precursors, respectively. These findings combined with a clinical history of myelofibrosis led to the final diagnosis of SEMHT. The presence of atypical megakaryocytes with immature hematopoietic cell morphology and a good understanding of the clinical history of the patient are essential to prevent misdiagnosis. The present case emphasizes the necessity of reviewing previous hematological history and considering clinical findings together with the associated pathological results.

Perianal skin Paget disease (PPD) is an unusual subtype of extramammary Paget disease, which is usually caused by a primary intraepithelial adnexal tumor and secondary spread from colorectal adenocarcinoma. The reports of secondary PPD associated with non‐invasive colorectal adenoma are rare. We report a rare case of non‐invasive colorectal‐adenoma‐associated PPD. In this case, the intraepithelial Paget cells of perianal skin manifested with colorectal phenotype by immunohistochemistry, and adjacent adenomas had high‐grade intraepithelial neoplasia but not invasion. Although this is a rare manifestation of PPD, understanding this phenomenon is important to prevent overdiagnosis and invasive overtreatment. Clinical management is variable and, therefore, close follow‐up examination is necessary.

Angioleiomyoma is a type of pericyte tumor with a benign biological behavior. It typically features proliferation of mature perivascular smooth muscle cells around blood vessels. Angioleiomyoma may be categorized into solid, cavernous or venous subtypes. Usually, it occurs in the dermis or subcutaneous tissue, while the rare cavernous subtype is most common in the upper extremities. Only a small number of cases of angioleiomyoma located in the mediastinum have been reported to date. In addition, there are few reports of mediastinal angioleiomyoma described as a cavernous histopathological subtype. The present study reported a case of mediastinal angioleiomyoma presenting as an unusual cavernous histopathological subtype. The histopathological and immunohistochemical features, based on which a diagnosis of cavernous angioleiomyoma was confirmed, were desmin-and smooth muscle actin-positive expression in spindle tumor cells, as well as ETS-related gene (ERG)-and CD31-positive expression in vascular endothelial cells. Cavernous angioleiomyoma of the mediastinum rarely occurs in the clinical setting but should be considered as a differential diagnosis of mediastinal tumors.