[A Case of Adenocarcinoma, HPV-independent, Mesonephric Type with Significant Response to Neoadjuvant Chemotherapy].

Adenocarcinoma, HPV-independent, mesonephric type (hereafter referred to as "mesonephric carcinoma") arising from the cervix is rare, its treatment has not been established, and its sensitivity to chemotherapy has not been fully investigated. Here we report on a 30-year-old female patient who presented at our hospital with a chief complaint of abnormal genital bleeding. We suspected cervical cancer. Based on examination, biopsy, and imaging, she was diagnosed with stage IIA2 adenocarcinoma of the cervix and was scheduled for surgery. Because she had a SARS-COV-2 infection, she was given two courses of paclitaxel-carboplatin (TC) therapy, based on the then-current surgical risk assessment after SARS-COV-2 infection, with a waiting period of at least 8 weeks. The patient was deemed to have a partial response and was treated with paclitaxel and carboplatin, after which she was deemed to have a partial response and underwent total hysterectomy. A diagnosis of stage IIA2 mesonephric carcinoma, ypT1b2N0M0, was made after histopathologic examination of an excised specimen. The patient was treated with 4 additional courses of TC therapy after surgery, and has had no recurrence in 13 months. We report a first case of response to neoadjuvant chemotherapy with TC regimen in a patient with mesonephric carcinoma of the cervix.

PDGFRB and NOTCH3 Mutations are Detectable in a Wider Range of Pericytic Tumors, Including Myopericytomas, Angioleiomyomas, Glomus Tumors, and Their Combined Tumors.

Pericytic tumors are subclassified as myopericytomas, myofibromas, angioleiomyomas, and glomus tumors according to the current World Health Organization classification. These pericytic tumors form a continuous morphologic spectrum, including those with combined morphology. However, to our knowledge, no widely accepted criteria for classifying tumors with combined morphology are available. Recent studies have identified platelet-derived growth factor receptor-beta (PDGFRB) gene mutations in a subset of myofibromas, myopericytomas, and myopericytomatoses but not in angioleiomyomas. NOTCH receptor 3 (NOTCH3) mutations have been reported in a subset of infantile myofibromatosis. To assess their potential role in classifying pericytic tumors, we investigated PDGFRB and NOTCH3 mutations in 41 pericytic tumors of variable morphology, including some combined forms. Our results show these mutations to be present in a variety of pericytic tumors, such as myopericytomas (PDGFRB, 3/11; NOTCH3, 4/11), myopericytomatoses (1/2; 1/2), myofibromas (3/6; 0/6), angioleiomyomas (2/13; 3/13), and glomus tumors (5/9; 1/9). Point mutations were identified in 3 tumors in PDGFRB exon 12 (Y562C, S574F, and G576S), 12 tumors in PDGFRB exon 14 (M655I, H657L, and N666K), and 9 tumors in NOTCH3 exon 25 (A1480S/T, D1481N, G1482S, T1490A, E1491K, G1494S, and V1512A). All PDGFRB mutations and NOTCH3 G1482S, T1490A, and G1494S mutations were classified as "deleterious/damaging" by ≥4 of 6 pathogenicity prediction tools in silico. Five-mutation-positive tumors, including 1 myopericytoma-angioleiomyoma, 2 myopericytomatoses-myofibroma, 1 myofibroma-myopericytoma and 1 angioleiomyoma-myopericytoma, were of combined morphology. Therefore, we found PDGFRB and NOTCH3 mutations to be detectable in a much wider variety of pericytic tumors than previously reported and confirmed myopericytomas, myofibromas, angioleiomyomas, and glomus tumors as members harboring PDGFRB or NOTCH3 mutations. Our results thus suggest that PDGFRB or NOTCH3 mutations are not useful for subclassifying members of the pericytic tumor family.

Potential pathogenetic link between angiomyofibroblastoma and superficial myofibroblastoma in the female lower genital tract based on a novel MTG1-CYP2E1 fusion.

Angiomyofibroblastoma and superficial myofibroblastoma are distinctive benign mesenchymal tumors occurring in the female lower genital tract. Despite their significant overlapping clinicopathologic features, including the presence of bland-looking spindle or oval cells with myofibroblastic or myoid differentiation, the tumors have been regarded as separate entities. Although subepithelial, hormone-sensitive mesenchymal cells of the female lower genital tract are considered as their potential common progenitor cells, their potential kinship or pathogenetic similarities remain elusive. Based on the identification of a novel RNA sequencing-based MTG1-CYP2E1 fusion transcript in an angiomyofibroblastoma index case, we investigated an additional ten samples of the tumor and its site-specific histological mimics, including eight superficial myofibroblastomas, four deep angiomyxomas, four cellular angiofibromas, three fibroepithelial stromal polyps, and eight non-site-specific mesenchymal tumors occurring in the female lower genital tract. Using reverse transcription-polymerase chain reaction, we showed that the MTG1-CYP2E1 fusion transcripts were consistently detectable in angiomyofibroblastomas (5/5, 100%) and often in superficial myofibroblastomas (3/5, 60%) but were not detected in the other examined site-specific or non-site-specific mesenchymal tumors. Our immunohistochemical experiments showed that CYP2E1, an isoenzyme belonging to the cytochrome P450 superfamily, exhibited increased positivity in tumors with MTG1-CYP2E1 than was observed in fusion-negative tumors (RR = 6.56, p = 0.001). The results of our study provide further evidence supporting the assertion that angiomyofibroblastoma and superficial myofibroblastoma represent phenotypic variants of site-specific mesenchymal tumors and share a common oncogenic mechanism.

Retroperitoneal dedifferentiated liposarcoma with huge cystic degeneration: A case report.

Prominent cyst formation is an unusual feature of liposarcoma. We report here a case of dedifferentiated liposarcoma with huge cystic change without preoperative chemo- or radiation therapy. The lesion arose in the retroperitoneum juxtaposed to the right kidney of a 67-year-old woman. She underwent a surgical removal of the retroperitoneal cyst. The cystic tumor contained 1600 mL of old bloody fluid, and its wall was composed of edematous, inflamed or sclerosing fibrous tissue with fatty tissue containing abundant atypical stromal cells, which were immunohistochemically positive for MDM2 and CDK4, and demonstrated MDM2 gene amplification by fluorescence in situ hybridization. The wall was contiguous to an atypical lipomatous nodule located in the mesentery. The following surgical specimens of the right hemicolectomy and right nephrectomy revealed atypical cells infiltrating into the subserosa of the colon and the perirenal fat tissue or that in the renal sinus. This case indicates that well differentiated or dedifferentiated liposarcoma should be also considered as a differential diagnosis of perirenal cystic mass.