A diminutive perivascular epithelioid cell tumor in the colon.

Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal tumor. Some papers have reported that colonoscopy could be used to treat PEComa with a predominantly pedunculated polyp, whereas surgical intervention is often required for cases with submucosal-type tumors. These findings suggest that the morphology of PEComa changes dramatically with disease progression. Because of the rapid progression of PEComa, endoscopic treatment remains challenging, and early-stage PEComa morphology is not well understood. A 64-year-old man presented to our hospital for a follow-up colonoscopy after undergoing multiple polypectomies. He had a medical history of colorectal adenoma and prostate cancer. A 4-mm pale blue elevated but not pedunculated lesion was observed in the transverse colon, an area where he had not had polyps previously. Since no epithelial change was observed, the presence of a submucosal tumor, such as a gastrointestinal stromal tumor, was suspected. Cold snare polypectomy was performed, and the lesion was completely resected. Histological evaluation using hematoxylin and eosin staining identified that the submucosal tumor included thickened vascular walls and adipose tissue. Although fragmented due to significant degeneration, spindle-shaped cells staining positive for smooth muscle actin were observed within and surrounding the unstructured hyalinized tissue with calcifications. Based on these findings, the lesion was diagnosed as angiomyolipoma, a subtype of PEComa. Complete resection was confirmed by histopathology. To our knowledge, this PEComa is the smallest of any PEComa reported in the literature. Our finding provides valuable insights into the very early stage of colorectal PEComas.

Phosphaturic Mesenchymal Tumor of the Greater Trochanter: A Case Report.

This is the case of a 56-year-old Hispanic male with a history of multiple fractures and electrolyte abnormalities, including hypophosphatemia and phosphaturia. Physical examination, imaging studies, and laboratory workup may have suggested the presence of a phosphaturic mesenchymal tumor (PMT) causing osteomalacia. The patient underwent surgery for en bloc tumor removal, and the histopathological analysis confirmed the presence of neoplastic cells consistent with PMT with minimal immunohistochemical positivity to S100 protein, which is atypical for this type of tumor. This case highlights the challenges in diagnosing PMTs due to their rarity and variable presentation. It emphasizes the importance of considering PMT in the differential diagnosis for unexplained hypophosphatemia and osteomalacia-like symptoms, especially in persistent disease after parathyroidectomy for presumed primary hyperparathyroidism. The atypical immunohistochemical profile observed in this case contributes to the growing body of knowledge about the heterogeneity of PMTs and underscores the need for comprehensive diagnostic approaches in suspected cases.

Renal Leiomyoma in a Female Adult: A Histopathological Case Report.

Renal leiomyomas are rare benign mesenchymal tumors that arise from the smooth muscle cells in the renal capsule, renal pelvis, and the smooth muscles of vessels in the kidney. They are usually found by accident during autopsies or on different imaging modalities made on other occasions. The clinical presentation may include hematuria and abdominal or flank pain, although renal leiomyomas are most frequently asymptomatic. This case concerns a 45-year-old woman with an asymptomatic tumor mass in the left kidney, discovered incidentally on an outpatient CT scan conducted on an unrelated occasion. Histological examination revealed well-demarcated tumor formation on regular hematoxylin and eosin (H&E) staining consisting of intersecting fascicles of spindle cells with blunt-ended, cigar-shaped nuclei and eosinophilic cytoplasm. The neoplasm showed no mitotic activity. Immunohistochemistry (IHC) was performed to exclude different spindle cell pathologies, such as solitary fibrous tumor of the kidney, primary leiomyosarcoma, and, less probably, sarcomatoid variants of renal cell carcinoma (RCC). Tumor cell cytoplasm was positive for h-caldesmon, smooth muscle actin (SMA), and desmin. The proliferation index Kiel-67 (Ki-67) was evaluated as less than 1%. Considering the microscopic description and the IHC results, the neoplasm was interpreted as a renal leiomyoma. In light of the rarity of these tumors, pathologists should consider differential diagnosis with precision. In challenging cases, immunohistochemical examination can be beneficial to distinguish between several spindle cell renal neoplasms, such as solitary fibrous tumor, leiomyosarcoma, sarcomatoid variant of RCC, fat-poor angiomyolipoma, benign peripheral nerve sheath tumors, renomedullary interstitial cell tumor, benign fibrous histiocytoma, primary angiosarcoma, mucinous tubular and spindle cell renal cell carcinoma (MTSRCC).

GLI1-altered Mesenchymal Tumor - Multi-omic Characterization of a Case Series and Patient-level Meta-analysis of 167 cases for Risk Stratification.

GLI1-altered mesenchymal tumors have recently emerged as a distinctive group of neoplasms characterized by GLI1 fusions or amplifications. While there is clearly metastatic potential, the clinicopathological features predicting for metastasis are currently unknown. Herein, we present 6 cases of GLI1-altered mesenchymal tumors with multiomics analysis. The median patient age was 50 years (range: 3 to 68). They arose from extremities and trunk (2/6), head and neck region (2/6), and gastrointestinal tract (2/6). Histologically, they featured uniform round-to-ovoid cells with nested architecture and a rich vascular network. One case displayed abundant multinucleated giant cells. All stained positive for GLI1 (5/5) and CD56 (6/6). Molecularly, they featured GLI1 fusion (5/6) and amplification (1/6). Fusion partner included ACTB (3/5), TXNIP (1/5) and novel TUBA1B (1/5). Multiomics analysis revealed they possessed distinct expression and epigenomic profiles. All the 6 cases had follow-up information, with 5 of them having no evidence of disease at median follow-up of 30 months (range 17.3 to 102 months), and one case being died of disease with regional neck lymph node and bilateral lung metastasis at 81.5 months of follow-up. By incorporating cases reported in the literature, we analyzed clinicopathological features of a total of 167 cases predictive of malignant behavior. We found that size ≥6 cm and mitotic count ≥ 5 per 10 high power fields are predicting of metastasis. Cases with both high-risk features had significantly poorer survival. This study expands the literature database of GLI1-altered mesenchymal tumors and identifies features which can be used for risk stratification.

Progressive bone pain caused by a phosphaturic mesenchymal tumor in the left femur: a case report and literature review.

Phosphaturic mesenchymal tumors (PMTs) are extremely rare mesenchymal tumors of soft tissue and bone that cause tumor-induced osteomalacia (TIO). Some of these tumors are completely asymptomatic and may grow undetected unless they become large enough to cause pain or discomfort. This type of tumor is crucial to diagnose in patients being treated for phosphate metabolism disorders and are a rare reason why patients seek medical help owing to pain. Here, we report the details of a patient with progressive bone pain caused by a PMT originating in the left femur.

Inflammatory Myofibroblastic Tumor of the Lung: A Case Report.

Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumor classified as an intermediate malignancy that rarely metastasizes. The most common site for IMTs is the lung, though they can develop in various other anatomical locations. Pulmonary IMTs are more common in children and adolescents and are infrequently diagnosed in adults. This case report describes a 49-year-old woman with a history of breast cancer previously treated with subtotal mastectomy and chemotherapy who developed an IMT in the lung. This case emphasizes the rarity of the disease and the associated clinical challenges when managing such cases.

Adult Prostate Sarcoma: Demographics, Treatment Patterns, and Survival.

BACKGROUND: This study aimed to examine clinicopathologic characteristics, treatment patterns, and survival rates in a contemporary population-based cohort of adult prostate sarcoma patients. METHODS: In the Surveillance, Epidemiology, and End Results database (2004-2020), adult patients with prostate sarcoma were identified. Descriptive statistics, Kaplan-Meier analyses, smoothed cumulative incidence plots, and Cox regression models were used. RESULTS: Of 125 patients, 45 (36%) harbored leiomyosarcoma, 17 (14%) had rhabdomyosarcoma, 15 (12%) had stromal sarcoma, 17 (14%) had sarcoma not otherwise specified (NOS), and 31 (25%) had other sarcoma subtypes. Metastatic stage was most common in the rhabdomyosarcoma patients (44%) and least common in the leiomyosarcoma (21%) and stromal sarcoma (20%) patients. Most of the rhabdomyosarcoma patients received the combination of systemic and radiation therapy with (24%) or without radical surgery (35%), whereas most of the leiomyosarcoma and stromal sarcoma patients underwent radical surgery with (22 and 13%) or without (22 and 47%) radiation. In the overall population, the median overall survival was 27 months. The 5-years overall versus cancer-specific versus other-cause mortality rates were respectively 71 versus 58 versus 13%. In the multivariable Cox regression models, the highest overall mortality was exhibited by the patients with metastatic disease (hazard ratio [HR] 2.87; 95% confidence interval [CI] 1.55-5.31; p < 0.001) or unknown disease stage (HR 2.94; 95% CI 2.20-7.21; p = 0.019). Conversely, of all the histologic subtypes, only stromal sarcoma distinguished itself by lower overall mortality (HR 0.41; 95% CI 0.18-0.96; p = 0.039). CONCLUSIONS: Four major histologic subtypes were identified. Among most adult sarcoma patients, treatment patterns vary according to histology, from multimodal therapy to radical prostatectomy alone. These treatment differences reflect equally important heterogeneity in survival patterns.

Perivascular epithelioid cell neoplasm (PEComa) of the urinary bladder presenting as urinary tract infection in a young woman.

PEComa is a rare mesenchymal tumor with unique features, sometimes manifesting in younger patients and can exhibit malignant transformation. We present a 24-year-old woman with urinary symptoms and hematuria. Imagining revealed a protruding mass in the bladder dome, raising suspicion for adenocarcinoma due to its location and vascular appearance. Pathology revealed PEComa. Clinicians should inquire about macroscopic hematuria and assess the entire urinary tract even in young patients with apparent urinary tract infection. Practitioners should be mindful of PEComa tumors, especially in cases involving young patients with tumors concerning the bladder dome. A variety of immunohistochemical techniques facilitate the diagnosis.

A Rare Case of Phosphaturic Mesenchymal Tumor Distal Femur in a Young Female.

Introduction: Phosphaturic mesenchymal tumors (PMTs) are rare bone neoplasms with diverse clinical presentations, often posing diagnostic challenges. Case Report: We describe the case of a 37-year-old female schoolteacher with a PMT localized in the distal femur. Diagnostic indicators included hypophosphatemia, hyperphosphaturia, elevated fibroblast growth factor-23 levels, and clinical symptoms of osteomalacia. Surgical management involved tumor resection and limb salvage surgery with a megaprosthesis. The post-operative period was uneventful, leading to a stable discharge. On follow-up, the patient showed no signs of recurrence, regained full ambulation, remained pain-free, and resumed teaching comfortably. Conclusion: This case highlights the importance of considering PMT in patients with unusual clinical symptoms, accompanied by hypophosphatemia, hyperphosphaturia, and osteomalacia, and demonstrates successful surgical management, leading to a favorable outcome.

Rare Intravascular Involvement of Pleomorphic Dermal Sarcoma Seen During Mohs Micrographic Surgery.

Pleomorphic dermal sarcoma (PDS) and atypical fibroxanthoma (AFX) are rare mesenchymal tumors that share similar clinical, histological, and immunohistochemical characteristics. Careful histopathological examination of a biopsy specimen that includes subcutaneous fat remains the preferred way to differentiate between these tumors. AFX is limited to dermal invasion, whereas PDS demonstrates deeper invasion. Moreover, PDS may present with tumor necrosis and high-grade histological findings, such as lymphovascular and perineural invasion, features absent in AFX. However, like PDS, AFX is a diagnosis of exclusion, and an exhaustive immunohistochemistry panel is recommended to distinguish these tumors from other spindled cell tumors in the differential diagnosis. The authors present the case of an 86-year-old man with biopsy-suspected AFX who was referred for Mohs micrographic surgery for tumor excision. During Mohs, the tumor was observed to have invaded deeply into the subcutaneous tissue and galeal aponeurosis, aligning more closely with a PDS. The diagnosis of PDS was confirmed using en face processing during Mohs surgery, which captured the intravascular involvement of a solitary vessel. Differentiating between PDS and AFX is important because PDS is a more aggressive tumor, with a higher rate of local recurrence and metastasis, and requires closer monitoring.

Mesenchymal Tumor Management: Integrating Surgical and Non-Surgical Strategies in Different Clinical Scenarios.

Mesenchymal tumors originate from mesenchymal cells and can be either benign or malignant, such as bone, soft tissue, and visceral sarcomas. Surgery is a cornerstone treatment in the management of mesenchymal tumors, often requiring complex procedures performed in high-volume referral centers. However, the COVID-19 pandemic has highlighted this need for alternative non-surgical approaches due to limited access to surgical resources. This review explores the role of non-surgical treatments in different clinical scenarios: for improving surgical outcomes, as a bridge to surgery, as better alternatives to surgery, and for non-curative treatment when surgery is not feasible. We discuss the effectiveness of active surveillance, cryoablation, high-intensity focused ultrasound, and other ablative techniques in managing these tumors. Additionally, we examine the use of tyrosine kinase inhibitors in gastrointestinal stromal tumors and hypofractionated radiotherapy in soft tissue sarcomas. The Sarculator tool is highlighted for its role in stratifying high-risk sarcoma patients and personalizing treatment plans. While surgery remains the mainstay of treatment, integrating advanced non-surgical strategies can enhance therapeutic possibilities and patient care, especially in specific clinical settings with limitations. A multidisciplinary approach in referral centers is vital to determine the optimal treatment course for each patient.

Massive cellular angiofibroma of the vulva: a case report.

Cellular angiofibroma is a rare benign mesenchymal tumor, typically occurring in the vulvar region of middle-aged women. This report highlights the importance of histological analysis in diagnosing this uncommon condition and emphasizes its benign nature and straightforward management. We present a case of a 58-year-old North African woman who had a large, well-defined mass in the left labia majora, which had been evolving over 2 years. MRI confirmed the resectability of the tumor by delineating its boundaries. The tumor, despite its slow growth leading to delayed diagnosis, was effectively treated with wide surgical excision. Diagnosis was confirmed through histological and immunohistochemical evaluations, revealing spindle cell proliferation with thick-walled vessels. Cellular angiofibroma, although initially alarming due to its size, is generally managed successfully with surgery and prognosis is favorable with a low risk of recurrence.

Solitary fibrous tumor of the pineal gland: a case report and review of the literature.

Solitary fibrous tumor (SFT) is a type of fibroblastic neoplasm that can occur in various parts of the body, with SFT of the pineal gland being exceedingly rare. We report the case of a 58-year-old male presenting with recurrent hiccups, acid reflux, and headache. Magnetic resonance imaging revealed an occupying lesion in the pineal region, suggestive of a neoplastic process. Intraoperatively, the lesion was located in the pineal region, exhibiting a grayish-red color, and was largely resected. Pathological examination confirmed the diagnosis of solitary fibrous tumor (CNS WHO Grade 1). Postoperatively, the patient was supplemented with radiotherapy, and long-term follow-up showed no signs of recurrence or metastasis.

Cellular angiofibroma of the female pelvic cavity: a case report.

BACKGROUND: Cellular angiofibroma is a rare benign mesenchymal tumor that mostly occurs in the genital area. Its occurrence outside this region, particularly in the pelvis, is extremely rare. To our knowledge, this study reports the first case of cellular angiofibroma occurring in the pelvic cavity, except for one case reported in the retroperitoneum. CASE PRESENTATION: A 25-year-old female patient with chronic, intermittent, dull pain in the lower abdomen that lasted for several months was referred to our clinic. Imaging studies revealed a tumor in the pelvic cavity anterior to the bladder. The radiographic characteristics of this tumor indicated a hypervascular nature, suggesting the possibility of a pheochromocytoma or a neuroendocrine tumor. The patient underwent surgical excision of the lesion. To date, no recurrence has been observed four months after excision. CONCLUSIONS: Cellular angiofibroma, although rare in the pelvic cavity, should be considered in the differential diagnosis of hypervascular pelvic space-occupying lesions. Immunohistochemical staining can help confirm the diagnosis of this condition. Treatment is generally straightforward, involving local excision of the tumor followed by postoperative monitoring.

Osteolytic mystery: A rare case of pathologic fracture from a phosphaturic mesenchymal tumor in hip and femur.

Phosphaturic mesenchymal tumor (PMT) is a rare tumor causing bone complications and myopathy. Histologically, PMT displays a mix of spindled cells, osteoclast-like giant cells, basophilic matrix, and flocculent or "grungy" calcification. Here we describe a case of PMT in the right hip and proximal femur, initially suspected to be multiple myeloma, presenting with osteolytic lesions and elevated alkaline phosphatase. Tests for malignancy were negative, but a subsequent biopsy confirmed PMT. The patient underwent hip biopsy, femur resection, and hemiarthroplasty, with follow-up MRI recommended.

PTH like substance secreting mesenchymal tumor causing oncogenic osteomalacia; unravelling the difficulties in localization - A report of 2 cases.

Background: Oncogenic osteomalacia is a rare paraneoplastic association of Phosphaturic mesenchymal tumor (PMT) secreting excessive levels of a PTH like substance. They usually remain undiagnosed and patients suffer for years. The rarity of this tumor and its non-specific clinical presentations poses great challenge to the treating surgeons. Its management is poorly described in literature. We report two of such rare cases without much diagnostic delay. Case report: We had 2 cases; A 53-year-old south east Asian male with 6 months of debilitating pain over multiple sites, and another 44-year-old male patient with complaints of low back ache, and pain over both lower and upper limbs for 1.5 years. Both had low serum phosphorus and elevated FGF-23 values, but all other parameters were normal. A PMT was suspected and confirmed on a Ga68- DOTATOC scan in both cases, and on complete excision, their symptoms and the altered blood parameters got normalized. Histology was consistent with PMT. Conclusion: Accurate and timely diagnosis of a PMT with non-specific features are extremely challenging, but not without solutions. Even though a tumor of rarity, with the appropriate imaging modalities like Ga68- DOTATOC scan, and estimation of FGF-23 and serum phosphorus levels, they can be diagnosed. Once identified, complete removal is often curative within a few months.

Uterine Mesenchymal Tumors: Updates on Pathology, Molecular Landscape, and Therapeutics.

Background: Mesenchymal uterine tumors are a diverse group of neoplasms with varying biological potential. Many of these neoplasms can have overlapping morphologic similarities, which, in some instances, render their diagnosis and categorization thorough histomorphologic examination inconclusive. In the last decade, an exponential amount of molecular data aiming to more accurately characterize and, consequently, treat these tumors have accumulated. Objective: The goal of this narrative review is to provide a pathologic review, a genetic update, and to know the new therapeutic avenues of primary uterine mesenchymal neoplasms.

Atypical Vaginal Aggressive Angiomyxoma in a Virgin: A Case Report from South Jordan.

Aggressive angiomyxoma is a locally invasive, rarely diagnosed mesenchymal tumor that predominantly affects the perineal region of women in their reproductive years. It is typically found in areas such as the vagina, vulva, and other pelvic soft tissues, but its presentation can be highly variable. We describe a particularly unique case of aggressive angiomyxoma, presenting in an atypical manner within the vaginal region of a 31-year-old virgin woman. This case is noteworthy for the unusual growth pattern of the angiomyxoma-located strictly within the vaginal epithelium, showing no signs of invasion into surrounding tissues, which is not typical of the aggressive nature of this type of tumor. The patient presented with a mass that protruded through the hymen, an uncommon presentation that led to initial speculation about the nature of the mass. The definitive diagnosis of aggressive angiomyxoma was made by meticulous histopathological examination after surgical excision of the mass. This case emphasizes the critical importance of considering aggressive angiomyxoma in the differential diagnosis of vaginal masses, particularly those that do not exhibit invasive characteristics. The case also highlights the need for increased awareness among clinicians about the potential for atypical presentations of this rare tumor, to facilitate timely and accurate diagnosis, and to guide appropriate management strategies. This report contributes to the growing body of literature on aggressive angiomyxoma, highlighting the variability in its presentation and the need to heighten suspicion in atypical cases.

Artificial Intelligence-Based Diagnosis of Gastric Mesenchymal Tumors Using Digital Endosonography Image Analysis.

Background/Objectives: Artificial intelligence (AI)-assisted endoscopic ultrasonography (EUS) diagnostic tools have shown excellent performance in diagnosing gastric mesenchymal tumors. This study aimed to assess whether incorporating clinical and endoscopic factors into AI-assisted EUS classification models based on digital image analysis could improve the diagnostic performance of AI-assisted EUS diagnostic tools. Methods: We retrospectively analyzed the data of 464 patients who underwent both EUS and surgical resection of gastric mesenchymal tumors, including 294 gastrointestinal stromal tumors (GISTs), 52 leiomyomas, and 41 schwannomas. AI-assisted classification models for GISTs and non-GIST tumors were developed utilizing clinical and endoscopic factors and digital EUS image analysis. Results: Regarding the baseline EUS classification models, the area under the receiver operating characteristic (AUC) values of the logistic regression, decision tree, random forest, K-nearest neighbor (KNN), and support vector machine (SVM) models were 0.805, 0.673, 0.781, 0.740, and 0.791, respectively. Using the new classification models incorporating clinical and endoscopic factors into the baseline classification models, the AUC values of the logistic regression, decision tree, random forest, KNN, and SVM models increased to 0.853, 0.715, 0.896, 0.825, and 0.794, respectively. In particular, the random forest and KNN models exhibited significant improvement in performance in Delong's test (both p < 0.001). Conclusion: The diagnostic performance of the AI-assisted EUS classification models improved when clinical and endoscopic factors were incorporated. Our results provided direction for developing new AI-assisted EUS models for gastric mesenchymal tumors.