Having limitations such as lacking of parity information which may affect the magnitude of risk estimates, this study demonstrates that ovarian endometriosis has a 4-fold increased risk of OC. Adenomyosis may associate with a 4- to 5-fold increased risk of OC and EC, and unexpectedly, a 13-fold increased risk of CRC.
Background
Solitary fibrous tumor (SFT) is a ubiquitous mesenchymal neoplasm but it rarely occurs in the parotid gland. The histological features are variable, with the majority having spindle cell morphology and non-specific branching (staghorn) ecstatic vascular pattern. SFT ranges from benign to overtly malignant. Dedifferentiation within SFTs represents an abrupt transition from a well-differentiated component to a high-grade area, the latter most often including poorly differentiated epithelioid/round cell or high-grade spindle cell morphology. To the best of our knowledge, dedifferentiated SFT in the parotid gland has not been previously reported.
Case presentation
A 33-year-old woman presented with a soft tissue tumor in the right parotid gland that had been present for 6 months. Fine needle aspiration (FNA) cytology indicated epithelioid morphology in the dedifferentiated component of the tumor, along with metachromatic myxoid matrix. The tumor was initially interpreted as a salivary gland neoplasm of uncertain malignant potential (SUMP).Right partial parotidectomy was performed, and microscopic examination of the resected specimen revealed a malignant spindle cell tumor with a central epithelioid/anaplastic component. The tumor cells were diffusely positive for CD34, STAT-6 and FLI-1, and negative for pan-cytokeratin, CAM5.2, p63, S100 protein, CD31, SMA, and calponin.ERG and Ki67 immunostaining showed an accentuated nuclear staining pattern in the central dedifferentiated area. There was no overexpression of p53 or p16. The patient is currently undergoing regular follow-up and is 11 months postresection with no evidence of recurrence or distant metastasis.
Conclusions
Unlike the typical spindle cell morphology of conventional SFTs, malignant SFTs can show areas of dedifferentiation mimicking an epithelial neoplasm. FNA of dedifferentiated SFTs of the parotid gland may show, a combination of atypical epithelioid cells and metachromatic myxoid/collagenous matrix, which is a less emphasized cytological feature of SFT and may lead to misdiagnosis as a more common parotid gland epithelial neoplasm.
Primary vaginal melanoma is a rare mucosal neoplasm, which is more aggressive than cutaneous melanoma. Information regarding its morphologic patterns is limited. In particular, the rhabdoid phenotype, mostly observed in metastatic or recurrent cutaneous melanomas, has yet to be reported at this anatomic location. Hence, a potential diagnostic difficulty may arise because of the inability to recognize this unusual histologic variant and its immunohistochemical aberrance. In this report, we describe the case of a primary vaginal melanoma in a 62-year-old woman, who exhibited both rhabdoid and small blue round cell morphologies, absence of S100 protein, and aberrant expression of desmin, CD56, and FLI-1. This report can facilitate the task of expanding the morphologic spectrum of vaginal melanoma, and prevent misdiagnosis and inadequate medical treatment.
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