An extremely rare case of a “primary endometrial adenocarcinoma with signet-ring cells” is presented in this study with microscopical images of the characteristic coexistence of the tumour and intermediate precancerous areas containing signet-ring cells.

Cancer stem cells (CSCs) are self-renewable and can be differentiated into different cell types. They play an important role in oncogenic signaling pathways, tumor cell heterogeneity, metastasis, and therapeutic resistance. Aldehyde dehydrogenase 1 (ALDH1) was identified as a specific marker for breast CSCs. The study included a total of 105 patients with a diagnosis of invasive ductal carcinoma (IDC) who underwent mastectomy and with sufficient pathology material for histopathological examination. Patient demographics, tumor location, tumor diameter, the presence of lymphovascular and perineural invasion and lymph node metastasis, surgical margin status, and immunohistochemistry (IHC) staining results were obtained from patients' records. The tumors were classified into IHC-based molecular subtypes according to the St. Gallen Consensus Conference in 2013. A four-tiered scoring system was used based on ALDH1 staining percentage in tumor cells. The tumor was determined as positive if the score was 2 or higher. Clinical, histopathological findings, and ALDH1 staining results were correlated. Twenty-five cases (23.8%) were ALDH1 positive. The ALDH1 positive group compared to the negative group was found to be associated with ER negativity (p = 0.044), but there was no correlation with other clinical and histopathological findings. ALDH1-positive IDCs may be less sensitive to hormonal therapy and associated with aggressive behavior.

We report a 70-year-old woman who presented a superficial spreading malignant melanoma with a nodular melanoma appearance, located on her leg. Most common clinicopathological types of malignant melanoma are lentigo maligna, superficial spreading, nodular, and acral lentiginous melanoma. Unusual variants of melanoma are rare but important. These are amelanotic melanoma, neurotropic melanoma, desmoplastic melanoma, metastatic melanoma, invisible melanoma, balloon cell melanoma, melanoma arising within a benign nevus and pedunculated melanoma. The lesion of our patient simulated a nodular or a pedunculated melanoma clinically, but its histopathological examination showed a superficial spreading melanoma arising from the surface of an Unna nevus. To the best of our knowledge, such misleading nodular appearance of a superficial melanoma arising from an intradermal nevus of Unna which seems to be a unique finding has not been reported previously.

Objective: This study aimed to evaluate diagnostic parameters such as mitotic count and tumor size in; leiomyosarcomas (LMSs) and benign uterine smooth muscle tumors (USMTs) and to define the diagnostic value and prognostic significance of the Ki-67 proliferation index and p16, p53, and bcl-2 expressions by immunohistochemical (IHC) methods. Materials and Methods:In total, 44 cases diagnosed as LMS, atypical leiomyoma, or cellular leiomyoma at our pathology department from January 2010 to December 2015 were included. IHC staining was performed for bcl-2, p16, p53, and Ki-67 using standard techniques.Results: Tumor size and mitotic index were significant prognostic factors (p=0.008 and p=0.001, respectively). The rate of diffuse p16 expression was significantly higher in the LMS group than in the other LM group (p=0.001). A Ki-67 positivity rate of >10% (increased proliferation) was statistically significantly higher in the LMS group than in the benign USMT group (p=0.0001). No statistically significant difference was found between the LMS and benign USMT groups with respect to bcl-2 expression (p=0.892). Mitotic count and high Ki-67 expression (>%10) were statistically high in cases with relapse/ metastasis (+) (p=0.0001 and p=0.0002, respectively). Conclusion:In addition to histopathological findings (tumor size and mean mitotic count), diffuse p16 expression and p53 overexpression can be used to distinguish between benign and malignant USMTs. A high mitotic index [≥10/10 (high-power field)] and high Ki-67 expression (>10%) can serve as useful indicators for diagnosing LMS, distinguishing benign tumors, and predicting an aggressive clinical course.

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