Ten-year follow-up of outcomes, patterns of care, and psychosocial burden in adolescent and young adult (AYA) patients with bone sarcomas from a large cohort in a low-income and middle-income country (LMIC).

BACKGROUND: The care of adolescents and young adults (AYAs) with bone sarcomas involves unique challenges. The objectives of this study were to identify challenges and evaluate long-term outcomes of these patients from India who received treatment with novel protocols. METHODS: This prospective cohort study included AYA patients (aged 15-39 years) with osteosarcoma and Ewing sarcoma (ES), who were treated uniformly at the authors' institute using unique protocols (OGS-12 and EFT-2001) from 2011 to 2021 and from 2013 to 2018, respectively. RESULTS: The cohorts included 688 of 748 (91.9%) treatment-naive AYA patients with osteosarcoma and 126 of 142 (88.7%) treatment-naive AYA patients with ES. Among 481 of 561 patients (85.7%) who had nonmetastatic osteosarcoma treated according to protocol, at a median follow-up of 59.7 months, the 5-year event-free survival (5-EFS) rate was 58.6% (95% confidence interval, 54.1%-63.5%) and for 142 patients (20.6%) who had metastatic osteosarcoma, the 5-EFS rate was 18.7%. The 5-EFS rate was 66.4% and 21.9% for 104 patients (73%) with nonmetastatic ES and 38 patients (27%) with metastatic ES, respectively. Treatment-naive patients had better outcomes, similar to compliance in the form of protocol completion (hazard ratio, 1.93 [p = .0043] and 2.66 [p < .0001], respectively. Only 230 of 377 (61.0%) male patients and 10 of 134 (7.4%) female patients reached out to fertility specialists. In addition, 17 of 161 (10.6%) eligible male survivors and 14 of 61 (22.9%) eligible female survivors got married posttreatment. Furthermore, 14 of 17 (82.4%) males and 14 of 14 (100%) females conceived. Among 311 patients who were working or attending school during diagnosis, greater than 90% had interruptions. CONCLUSIONS: Homogenous treatment with the OGS-12 and EFT-2001 protocols resulted in internationally comparable long-term outcomes in the cohorts with nonmetastatic and metastatic AYA bone sarcomas. Treatment compliance, timely referral to sarcoma reference centers (avoiding prior inadvertent treatment), and streamlining fertility-preservation practices constitute unmet needs that demand prioritization.

The BCOR-rearranged sarcoma involving the lung: Diagnosis with clinical outcome and literature review.

ABSTRACT: BCOR-rearranged sarcomas (BRS) constitute relatively newly described sarcomas, which, within the musculoskeletal sites, usually occur in the bones, followed by soft tissues. Primary BRS involving the visceral organs is very rare, and only a single case is reported in the lung. These tumors share overlapping morphological and immunohistochemical (IHC) features with other neoplasms, such as synovial sarcoma, Ewing sarcoma, as well as carcinosarcoma, the latter especially when occurring in the visceral organs. BCOR immunostaining is useful in triaging a tumor for molecular diagnosis, which constitutes the "essential" diagnostic criterion for these tumors. To report an extremely rare case of a BRS, confirmed by BCOR-rearrangement by fluorescence in situ hybridization (FISH), primarily occurring in the lung, emphasizing the diagnostic approach and management, along with review of literature. An18-year-old boy presented with complaints of left-sided chest pain, along with cough, fever, loss of appetite, and weight. On radio imaging, there was a complete collapse of the left lower lobe of lung with moderate pleural effusion. The biopsy showed a biphasic tumor comprising primitive round cells admixed with spindle cells. Immunohistochemically, the tumor cells were positive for BCOR, TLE1, and p53. FISH showed BCOR gene rearrangement. A diagnosis of primary BRS of lung was offered. The patient had a favorable response to the chemotherapy regime. BRS is an ultra-rare tumor, which rarely involves visceral organs. The lung is an exceptionally rare site, with only single reported case previously. An exact confirmation by molecular testing has treatment-associated implications. A review of similar reported cases is presented herewith.

Vulvo-vaginal stromal tumours - Case series of a rare entity from an oncology centre in India.

Vulvo-vaginal stromal tumours are a rare and diverse group of mesenchymal neoplasms unique to hormone-responsive stroma of the vulva and vagina. These tumours are mostly benign, except for the locally aggressive deep angiomyxomas. Often these tumours pose diagnostic challenges, resembling certain malignant vulvo vaginal tumours. This case series highlights clinicopathological features of four angiomyxomas; a single angiomyofibroblastoma, and another superficial myofibroblastoma, including their clinical outcomes. All patients were in their 4th or 5th decade of life. Only 1/4 angiomyxomas was correctly diagnosed at the referring hospitals. Three out of four patients harbouring angiomyxomas achieved clinical remission post-surgery, while one patient was lost to follow-up. By immunohistochemistry, tumor cells showed variable positivity for desmin, SMA, ER, and PR, and negativity for S100P and CD34. The angiomyofibroblastoma was initially misdiagnosed as a liposarcoma, and the patient was lost to follow-up after diagnosis. Immunohistochemically, the tumor cells were diffusely positive for SMA and ER; weakly and focally positive for desmin, and negative for AE1/AE3, CD34, and S100P. The patient with superficial myofibroblastoma is in clinical remission post-excision with an 18-month follow-up. Immunohistochemically, the tumor cells showed CD34 positivity. Therapeutically, none of the patient received adjuvant treatment, except for a single patient with angiomyxoma, who underwent chemoradiation for a synchronous cancer cervix post-surgery. This case series provides valuable insights into the clinical heterogeneity, diagnostic intricacies, and outcomes of vulvo-vaginal stromal tumours from an oncology centre in India, further contributing to a better understanding of these rare tumours.

Autophagy-mediated ID1 turnover dictates chemo-resistant fate in ovarian cancer stem cells.

BACKGROUND: The mechanisms enabling dynamic shifts between drug-resistant and drug-sensitive states in cancer cells are still underexplored. This study investigated the role of targeted autophagic protein degradation in regulating ovarian cancer stem cell (CSC) fate decisions and chemo-resistance. METHODS: Autophagy levels were compared between CSC-enriched side population (SP) and non-SP cells (NSP) in multiple ovarian cancer cell lines using immunoblotting, immunofluorescence, and transmission electron microscopy. The impact of autophagy modulation on CSC markers and differentiation was assessed by flow cytometry, immunoblotting and qRT-PCR. In silico modeling and co-immunoprecipitation identified ID1 interacting proteins. Pharmacological and genetic approaches along with Annexin-PI assay, ChIP assay, western blotting, qRT-PCR and ICP-MS were used to evaluate effects on cisplatin sensitivity, apoptosis, SLC31A1 expression, promoter binding, and intracellular platinum accumulation in ID1 depleted backdrop. Patient-derived tumor spheroids were analyzed for autophagy and SLC31A1 levels. RESULTS: Ovarian CSCs exhibited increased basal autophagy compared to non-CSCs. Further autophagy stimulation by serum-starvation and chemical modes triggered proteolysis of the stemness regulator ID1, driving the differentiation of chemo-resistant CSCs into chemo-sensitive non-CSCs. In silico modeling predicted TCF12 as a potent ID1 interactor, which was validated by co-immunoprecipitation. ID1 depletion freed TCF12 to transactivate the cisplatin influx transporter SLC31A1, increasing intracellular cisplatin levels and cytotoxicity. Patient-derived tumor spheroids exhibited a functional association between autophagy, ID1, SLC31A1, and platinum sensitivity. CONCLUSIONS: This study reveals a novel autophagy-ID1-TCF12-SLC31A1 axis where targeted autophagic degradation of ID1 enables rapid remodeling of CSCs to reverse chemo-resistance. Modulating this pathway could counter drug resistance in ovarian cancer.

An octad of fumarate hydratase-deficient uterine leiomyomas: Case series with review of literature from a single institution.

BACKGROUND: Fumarate hydratase (FH)-deficient (FH-d) leiomyomas are included in the recent World Health Organization fascicle of the female genital tumors. These are known to be associated with hereditary leiomyomatosis and renal cell cancer (HLRCC) syndrome. The tumors can be diagnosed based on certain histopathological features, along with loss of immunohistochemical expression of FH immunostain in most tumors. Currently, there is no documentation on these tumors from our subcontinent. AIMS: We analyzed eight FH-d leiomyomas diagnosed at our institute. RESULTS: The most common presentation was vaginal bleeding (menorrhagia). Pelvic ultrasonogram revealed multiple fibroids in most patients except in two, who harbored a single fibroid. The size of these fibroids ranged from 3 to 19 cm. Five patients underwent myomectomies, while three underwent a total abdominal hysterectomy and bilateral salphino-ophorectomy. The most consistently observed histopathological features were hemangiopericytomatous vascular patterns, cytoplasmic globules, increased cellularity, distinct eosinophilic nucleoli, and cytological atypia (8/8, 100% tumors), followed by multinucleate giant cells and perivascular edema, seen in 62% and 50% tumors, respectively. Immunohistochemically, all tumors were positive for desmin, smooth muscle actin, and h-caldesmon and showed loss of FH immunostain, along with low Ki-67/MIB1. None of those patients had any renal or cutaneous manifestations. CONCLUSIONS: This constitutes the first such study from the Indian subcontinent and reinforces that although uterine leiomyomas constitute an integral component of the diagnosis of HLRCC syndrome, these occur in the absence of renal or cutaneous manifestations. FH-d uterine leiomyomas are more likely sporadic and could be a false alarm to raise the possibility of HLRCC with their exclusive presence.

EWSR1::ATF1 fusions characterize a group of extra-abdominal epithelioid and round cell mesenchymal neoplasms, phenotypically overlapping with sclerosing epithelioid fibrosarcomas, and intra-abdominal FET::CREB fusion neoplasms.

With the increasing use of next generation sequencing in soft tissue pathology, particularly in neoplasms not fitting any World Health Organization (WHO) category, the spectrum of EWSR1 fusion-associated soft tissue neoplasms has been expanding significantly. Although recurrent EWSR1::ATF1 fusions were initially limited to a triad of mesenchymal neoplasms including clear cell sarcoma of soft tissue, angiomatoid fibrous histiocytoma and malignant gastrointestinal neuroectodermal tumor (MGNET), this family has been expanding. We herein describe 4 unclassified extra-abdominal soft tissue (n = 3) and bone (n = 1) neoplasms displaying epithelioid and round cell morphology and carrying an EWSR1::ATF1 fusion. Affected were 3 males and 1 female aged 20-56 years. All primary tumors were extra-abdominal and deep-seated (chest wall, mediastinum, deltoid, and parapharyngeal soft tissue). Their size ranged 4.4-7.5 cm (median, 6.2). One patient presented with constitutional symptoms. Surgery with (2) or without (1) neo/adjuvant therapy was the treatment. At last follow-up (8-21 months), 2 patients developed progressive disease (1 recurrence; 1 distant metastasis). The immunophenotype of these tumors is potentially misleading with variable expression of EMA (2 of 3), pankeratin (2 of 4), synaptophysin (2 of 3), MUC4 (1 of 3), and ALK (1 of 3). All tumors were negative for S100 and SOX10. These observations point to the existence of heretofore under-recognized group of epithelioid and round cell neoplasms of soft tissue and bone, driven by EWSR1::ATF1 fusions, but distinct from established EWSR1::ATF1-associated soft tissue entities. Their overall morphology and immunophenotype recapitulate that of the emerging EWSR1/FUS::CREB fusion associated intra-abdominal epithelioid/round cell neoplasms. Our cases point to a potentially aggressive clinical behavior. Recognizing this tumor type is mandatory to delineate any inherent biological and/or therapeutic distinctness from other, better-known sarcomas in the differential diagnosis including sclerosing epithelioid fibrosarcoma.

YAP1∷KMT2A fusion-positive sarcoma: An emerging soft tissue tumor entity with morphological features resembling a sclerosing epithelioid fibrosarcoma.

ABSTRACT: Sclerosing epithelioid fibrosarcoma (SEF) and low-grade fibromyxoid sarcoma (LGFMS) constitute a morphological continuum with certain overlapping histopathological features and MUC 4 immunopositivity. SEF is characterized by EWSR1 gene rearrangement, is relatively more aggressive and shows a limited response to chemotherapy. Lately, a subset of tumors with morphological features of SEF, but lacking MUC4 immunostaining and EWSR1 gene rearrangement have been observed. We report the first case of YAP1∷KMT2A-positive sarcoma from the Indian subcontinent along with a review of similar tumors reported previously. A case of 31-year-old male presented with a 3 cm painful lump in the right suboccipital region. Histopathological examination of the excised specimen revealed a cellular tumor composed of atypical spindle and epithelioid cells, exhibiting moderate nuclear pleomorphism, arranged in cords, embedded in a dense collagenous/hyalinized stroma. By immunohistochemistry, the tumor cells were diffusely positive for cyclin D1 and negative for MUC4, desmin, myogenin, ß-catenin, STAT6, myoD1, SMA, and S100P. By fluorescence in-situ hybridization, EWSR1 gene rearrangement was negative. Next-generation sequencing (NGS) revealed YAP1exon5∷KMT2Aexon4 fusion. Given a positive resection margin, he underwent a revision surgery involving wide local excision of the lesion including the outer table of the occipital bone followed by image-guided radiation therapy. Over 2 years of his follow-up, the patient is alive with no evidence of recurrence. Thus, YAP1∷KMT2A positive sarcomas have distinct molecular and overlapping histopathological features with SEF, with relatively less aggressive disease course. Documentation of additional similar tumors with long-term follow-up is required.

Clear cell adenocarcinoma of the cervix and its mimickers - A series of 19 cases from a tertiary care referral centre in India.

ABSTRACT: Clear cell adenocarcinoma (CCAC) of cervix is a rare subtype of endocervical adenocarcinoma that accounts for 4% of all cervical adenocarcinoma with many morphological mimickers. Retrospectively study cases of cervical clear cell adenocarcinoma of the cervix. Clinical profile and pathological features of CCAC of the cervix diagnosed between 2018-2022 were retrospectively analyzed.The database of the Department of Pathology of our institute was systematically searched for patients diagnosed with clear cell adenocarcinoma of the cervix during 2018-2022.A total of 19 patients were studied with the mean age of patients being 53.72 years (range 25 -84 yrs,standard deviation-25.9) and median tumor size being 5.6cm. Lymph node metastasis was identified in 33.3% and distant metastasis were seen in 20% of the cases. Staging could not be done in 4 cases.FIGO staging of the cases included IB1(2 cases), IB2(2 cases), IIB (3 cases),IIIA (1 case)IIIB(4 cases),and IV(3 cases). On histopathological evaluation, heterogeneous architectural pattern comprising of tubulocystic, solid, and papillary patterns were seen in 13 cases (13/19,68.4%). Pure tubulocystic (3/19,15.7%), pure papillary (2/19,10.5%), and pure solid patterns (1/19,5.3%) were also identified. Tumor cells with clear cytoplasm ranged from 5% to 95%. Nuclear atypia was moderate to marked in all the cases (19/19,100%). Mitotic activity varied from 1/10hpf to 20-22/10hpf. By immunohistochemistry, tumor was positive for Napsin A in all the cases,p16INK4a was negative in majority of cases (15/19,78.9%) and ER was negative in 14 cases (14/19,73.7%) .p53 showed wild type staining except for one case . Clear cell adenocarcinoma being a rare subtype of cervical adenocarcinoma, needs to be differentiated from other Human Papilloma Virus(HPV) independent adenocarcinomas (gastric and mesonephric types) and benign entities such as endocervical glandular Arias-Stella reaction. Judicious use of a panel of immunostains is often helpful.

Spindle Cell Lipoma and Pleomorphic Lipoma in the Head and Neck: A Comprehensive Study of Six Cases With Review of Literature.

BACKGROUND: Spindle cell lipomas (SL) and pleomorphic lipomas (PL) are rare variants of lipomas, occurring predominantly in the head and neck region. Laryngeal SL/PL is very uncommon and causes obstructive symptoms needing immediate intervention. These tumors are often challenging in radiology due to the admixture of elements and the presence of adipose tissue may help in diagnosis. From a surgeon's perspective, understanding the nuances of SL/PL is paramount. Histology is the gold standard for diagnosis; however, it often causes diagnostic challenges in biopsy.  Method: A retrospective review of the clinical and pathologic features of archival cases of SL/PL was performed. RESULTS: A total of six cases of head and neck region SL/PL were identified. The age of patients ranged from 21 to 58 years and the male-to-female ratio was 5:1. The tumors were distributed in the nape of the neck (n=3), laryngeal region (n=2), and orbit (n=1). Histology in all the cases showed a low-grade neoplasm composed of a variable amount of spindle cells and adipose tissue. The stroma was myxoid in most cases. CD34 was diffusely positive in all the cases. CONCLUSION: SLs are a rare and uncommon variant of lipoma with a predilection in the head and neck region. They are low-grade neoplasms with a propensity to recur after years. Having knowledge of this tumor can improve surgical outcomes and better patient care.

Evaluation of Metronomic Therapy as a Low-Cost, Sustainable, Standard-of-Care Option in Desmoid Fibromatosis: Real-World Data From a Tertiary Care Center in India.

PURPOSE: Desmoid fibromatosis (DF) is a locally aggressive tumor with low mortality but significant morbidity. There is a lack of standard of care, and existing therapies are associated with significant barriers including access, cost, and toxicities. This study aimed to explore the efficacy and safety of the metronomic therapy (MT) in DF in a large, homogenous cohort from India. PATIENTS AND METHODS: This study involved histologically confirmed DF cases treated with MT comprising vinblastine (6 mg) and methotrexate (15 mg) both once a week, and tamoxifen (40 mg/m2) in two divided doses once daily between 2002 and 2018. RESULTS: There were 315 patients with a median age of 27 years; the commonest site was extremity (142 of 315; 45.0%). There were 159 (50.1%) male patients. Of the 123 (39.0%) prior treated patients, 119 had surgery. Of 315 patients, 263 (83.5%) received treatment at our institute (MT-151, 77-local treatment, 9-tyrosine kinase inhibitor, and 26 were observed). Among the MT cohort (n = 163, 61.2%), at a median follow-up of 36 (0.5-186) months, the 3-year progression-free and overall survival were 81.1% (95% CI, 74.3 to 88.4) and 99.2% (95% CI, 97.6 to 100), respectively. There were 35% partial responses. Ninety-two patients (56.4%) completed 1-year therapy, which was an independent prognosticator (P < .0001; hazard ratio, 0.177 [95% CI, 0.083 to 0.377]). MT was well tolerated. Predominant grade ≥3 toxicities were febrile neutropenia, 12 (7.4%) without any chemotoxicity-related death. The annual cost of MT was $130 US dollars. CONCLUSION: The novel, low-cost MT qualifies as one of the effective, less toxic, sustainable, standard-of-care options for the treatment of DF with global reach and merits wide recognition.

Malignant Transformation in a Chondroblastoma-Does it Exist?

Chondroblastoma is currently described as a benign bone tumor, histopathologically characterized by its classical features including chondroblasts, pink cartilage, and a variable number of osteoclast-like giant cells with foci of dystrophic calcification. Although recurrent and metastasizing chondroblastomas are reported, a malignant chondroblastoma is exceedingly rare and somewhat a contentious entity. A 35-year-old male presented with a lump in his ankle of 15 years' duration. Imaging disclosed a lytic destructive lesion involving the lower ends of the tibia and fibula with a soft tissue component, indicative of atypical/"worrisome" features. Microscopic examination of the biopsy revealed distinct foci of chondroblastoma, transitioning to areas of high-grade sarcoma, including pleomorphic cells, increased mitoses, and prominent stromal hyalinization. Immunohistochemically, the entire tumor was positive for H3K36M, while DOG1 highlighted the areas of chondroblastoma. SATB2 highlighted the areas of high-grade sarcoma, sparing the areas of chondroblastoma. Additionally, the areas of a high-grade sarcoma showed multifocal desmin immunostaining. A diagnosis of a malignant transformation in a chondroblastoma was offered. The patient defaulted to further treatment and unfortunately died 8 months, post-diagnosis. The conceptual evolution of a malignant chondroblastoma with H3K36M immunostaining in the few reported tumors is described herewith.

A Rare Case of a Malignant Epithelioid Neoplasm With an Underlying Novel EWSR1::ZBT44 Fusion, Identified on Next-Generation Sequencing (NGS).

The clinicopathological spectrum of undifferentiated round cell sarcomas of bone and soft tissues is expanding after the 5th edition of the WHO classification. A 23-year-old male patient presented with a lump in his left thigh of 3 months' duration. Radiological examination revealed a well-defined, solid-cystic lobulated, soft tissue lesion in the proximal medial region of his left thigh, measuring 7.7 cm in the largest dimension. The referring diagnosis was an epithelioid sarcoma. Histopathological review of the tumor sections revealed a cellular tumor composed of malignant epithelioid to focally "rhabdoid-like" cells in a variable hyalinized and myxoid stroma with geographic areas of necrosis. In addition, there were areas reminiscent of hemangiopericytomatous vasculature. By immunohistochemistry, the tumor cells were diffusely positive for CD34, focally and distinctly for pan keratin (AE1/AE3). INI1/SMARCB1 and SMARCA4 (BRG1) were diffusely positive (normal). Next-generation sequencing with a wide sarcoma panel revealed EWSR1exon8::ZBT44exon4 fusion. The present example constitutes the first malignant epithelioid tumor with a hemangiopericytomatous growth pattern, exhibiting this rare fusion. The differential diagnoses of this tumor and their corresponding immunohistochemical profile are discussed. This example highlights the value of NGS in unraveling rare fusions and in differentiating these tumors from their several mimics.

Immunohistochemical expression of H3.3 G34W in 100 giant cell tumors of bone and its diagnostic mimics, including its value in resolving uncommon diagnostic scenarios: A single institutional study at a tertiary cancer referral center, India.

BACKGROUND: There can be a diagnostic challenge in differentiating giant cell tumor of bone (GCTB) from its mimics. Lately, histone H 3 F 3 A (Histone 3.3 ) G34W has been identified as a promising immunohistochemical marker. AIMS: This study was aimed at evaluating H3.3 G34W immunostaining in 100 GCTBs, including its value in resolving diagnostic dilemmas. MATERIALS AND METHODS: Immunohistochemical staining for H3.3 G34W was graded in terms of staining intensity (1+ to 3+) and the percentage of tumor cells showing crisp nuclear staining. RESULTS: One hundred GCTBs occurred in 58 males and 42 females (M: F ratio = 1.3), of 7-66 years age (average = 31.3, median = 28), commonly in distal femur (26), followed by proximal tibia (17), distal radius (12), proximal humerus (7), metacarpals (7), sacrum (6), proximal fibula (6), and relatively unusual sites (19), including a single multicentric case. Out of 92 GCTBs, wherein H3.3 G34W immunostaining worked, 81 (88.1%) showed positive staining in the mononuclear cells, including tumors with fibrous histiocytoma-like areas, sparing osteoclast-like giant cells, with 3+ staining intensity in 65/81 (80%) tumors. All 7/7 (100%) malignant GCTBs showed positive staining, including the pleomorphic/sarcomatous cells. All 7/7 (100%) metastatic GCTBs showed positive immunostaining. Seven out of 10 post-denosumab treated GCTBs showed positive H3.3 G34W immunostaining in the residual mononuclear cells. None of the other 37 "giant cell-rich" lesions displayed H3.3 G34W immunostaining. Four of 9 GCTBs tested for H3.3 G34W mutation showed positive results. CONCLUSIONS: The diagnostic sensitivity and specificity of H3.3 G34W for GCTB were 88.1% and 100%, respectively. This constitutes one of the first reports from our country, further validating the diagnostic value of H3.3 G34W in differentiating GCTB, including metastatic and malignant forms from its mimics, including small biopsy samples. Its value in various diagnostic dilemmas is presented and utility in identifying residual tumor cells in post-denosumab treated GCTBs is worth exploring.

Poorly differentiated biphasic synovial sarcoma of the vulva, displaying SS18::SSX1 fusion and weak to absent (mosaic) INI1/SMARCB1 immunostaining: A rare case with literature review.

ABSTRACT: Synovial sarcoma (SS) is rarely documented in the female genital tract, especially confirmed by molecular testing for SYT::SSX translocation and TLE1 immunostaining. A 62-year-old lady presented with a progressively increasing lump and pain over her right groin, for 6-month duration. Radiologically, a well-defined, solid-cystic mass was seen involving the right labia with necrotic areas, sparing the underlying muscles and the overlying skin. She underwent a biopsy followed by a surgical excision. Histopathologic examination revealed a spindle cell sarcoma, including tumor cells exhibiting a prominent hemangiopericytomatous pattern. There were focal areas of epithelial differentiation (pseudoglandular) along with areas of round cell morphology and increased mitoses (poor differentiation) in the resected specimen. Immunohistochemically, the tumor cells were diffusely positive for TLE1, patchily positive for pan keratin (AE1/AE3) and EMA, the latter more in the areas of epithelial differentiation, while negative for CD34, SMA, desmin, S100P, and SOX10. INI1/SMARCB1 showed a characteristic weak to absent (mosaic) staining pattern. Furthermore, the tumor displayed SS18::SSX 1 fusion by RT-PCR. This constitutes one of the few reported cases of vulvar SS, confirmed by molecular testing and the first documented vulvar SS showing a mosaic pattern of INI1/SMARCB1 immunostaining. A review of the literature and diagnostic implications are presented herewith.

Phosphaturic mesenchymal tumor: Clinicopathological features with outcomes in 10 patients with review of literature.

BACKGROUND: Phosphaturic mesenchymal tumors (PMTs) are rare mesenchymal tumors, associated with long-standing, non-specific but often debilitating symptoms in the affected patients. These tumors display characteristic histopathological features and in case, identified timely, can be a boon for patients, given an excision is completely curative. AIMS: To evaluate the clinical and histopathological features of 10 PMTs, diagnosed at our institution, along with clinical outcomes in those patients. MATERIALS AND METHODS: This was a retrospective study, wherein 10 PMTs, diagnosed from January 2013 to July 2022, were included. RESULTS: The average age at the time of diagnosis was 40 years with an M:F ratio of 4:1. Clinical features included lumps, weakness, bone pain, difficulty in moving and walking, and pathologic fractures. The biochemical analysis showed normal serum calcium levels (average = 9.5 mg/dL), with low serum phosphorus (average = 2.2 mg/dL) and raised serum fibroblast growth factor 23 (FGF23) levels, in all the cases, wherever available. On histopathology, all tumors showed cells arranged in a hemangiopericytomatous pattern, including oval to short spindle forms. Multinucleate giant cells were present in nine tumors, and characteristic "grungy calcifications" was observed in eight tumors. Prominent pseudo cystic spaces were seen in eight tumors. A significant number of mitotic figures and tumor necrosis were not seen in any tumor. In five cases where follow-up was available, there was complete resolution of symptoms post-resection with no recurrence or metastasis. All those patients were free of disease until the last follow-up. CONCLUSION: This constitutes the first largest comprehensive study on these rare tumors from our country. PMTs can be diagnosed based on certain histopathological features and correlation with clinicoradiological and biochemical findings. These are invariably benign neoplasms. Patients are relieved of their debilitating symptoms after adequate surgical tumor resection. Therefore, their correct and timely diagnosis is crucial.

Clinicopathological Features of Three Rare EWSR1::NFATC2 Sarcomas of Bone and Soft Tissues.

Certain undifferentiated round cell sarcomas displaying EWSR1::NFATC2 fusion have recently been reported, mostly in the bones. This report presents clinicopathological features of 3 additional EWSR1::NFATC2 fusion sarcomas of bone and soft tissues. We present 2 soft tissue and 1 bone tumors: A 62-year-old man with pain and a slowly growing, 8-cm-sized soft tissue mass in the anterolateral compartment of his right calf, along with multiple pulmonary metastatic lesions; a 63-year-old man with a 5-cm sized axillary mass of 4 months duration and a cystic renal mass; and a 53-year-old man with a complaint of leg pain was found to have a 2-cm diameter, intramedullary, lytic mass in the diaphysis of his left femur. Microscopic examination of the tumors in all patients revealed round to epithelioid cells arranged in cords and trabeculae in a myxohyaline stroma. Immunohistochemically, the tumor cells were positive for MIC2/CD99 (3/3), EMA (3/3), NKX3.1 (3/3), NKX2.2 (2/2), CD10 (2/2), and aggrecan (1/1), while negative for S100P and GFAP. Various keratins were also negative except focal AE1/AE3 positivity in the third tumor. By fluorescence in-situ hybridization, 2 tumors (#1 and #3) revealed EWSR1 gene rearrangement and amplification. Furthermore, 2 tumors (#1 and #2) displayed EWSR1ex8::NFATC2ex3 fusion with next-generation sequencing (NGS). The first patient was offered chemotherapy. However, he died of pulmonary metastasis. This report highlights the value of combining histopathological features and immunostains such as NXK3.1, NKX2.2, CD10, and aggrecan, along with EWSR1 testing for triaging these tumors for rare gene fusions by NGS that has prognostic implications.

Clinicopathological features of two ultra-rare cases of malignant perivascular epithelioid cell tumors (PEComas) involving the uterus with recent updates.

Malignant perivascular epithelioid tumors (PEComas) involving the uterus are uncommon. Herein, we present the clinicopathological features of two such cases, including their diagnostic implications with recent updates. A 62-year-old lady presented with vaginal bleeding. Ultrasonogram revealed a heterogeneous uterine mass. She underwent an endometrial biopsy and total abdominal hysterectomy with bilateral salpingo-oophorectomy (TAH-BSO), which revealed a 3.2 cm-sized proliferative tumor in the fundus. A 45-year-old lady presented with recurrent abdominal pain. She underwent cytoreductive surgery twice with adjuvant chemotherapy for multiple tumors and TAH-BSO for a uterine tumor, 2 years before. Microscopic examination of both tumors revealed markedly atypical, polygonal-shaped/epithelioid tumor cells containing eosinophilic cytoplasm and arranged in a nesting pattern with intervening thin-walled blood vessels, mitotic figures (≥ 6/10 high power fields (hpfs)), and tumor necrosis. Tumor infiltration was more than half the myometrial thickness in the first tumor and pelvic nodal metastasis. The second tumor revealed rhabdoid-like and vacuolated cells along with "spider-like" giant cells. Immunohistochemically, both the tumors were positive for HMB45 and desmin, while negative for epithelial markers. Additionally, the second tumor was positive for smooth muscle actin (SMA) and TFE3. Both patients developed tumor recurrences. In view of multiple tumor deposits, the second patient was induced with a mammalian target of rapamycin (m-TOR) inhibitor (everolimus) but unfortunately died of the disease. Malignant PEComas involving the uterus are ultra-rare, aggressive tumors. An index of suspicion, based on certain histomorphological features, supported by immunohistochemical expression of myomelanocytic markers is necessary for a correct diagnosis. Certain PEComas display TFE3 positivity. A correct diagnosis has significant implications, including an aggressive clinical course and the possibility of targeted therapy, especially in recurrences or metastasis.

Correction: Mukherjee et al. Homo and Heterotypic Cellular Cross-Talk in Epithelial Ovarian Cancer Impart Pro-Tumorigenic Properties through Differential Activation of the Notch3 Pathway. Cancers 2022, 14, 3365.

In the original publication [...].

Pitfalls in soft tissue cytopathology.

Fine needle aspiration biopsy (FNAB) is a diagnostic modality for the evaluation of suspicious soft tissue masses. Despite its reasonable sensitivity, specificity and positive predictive value in differentiating benign from malignant neoplasms, the exact subtyping of the primary soft tissue tumours can be challenging. Certain tumours constitute "pitfalls" and add to the diagnostic challenge. This review provides a detailed account of the diagnostic challenges in soft tissue cytopathology, including pitfalls and, more importantly, the ways to overcome these challenges by integrating clinical details, key cytomorphological features and judicious application of ancillary techniques.