Feline Facial Spindle Cell Tumors in 29 Cats: Histomorphological and Immunohistochemical Characterization

Soft tissue tumors/sarcomas (STSs) in felines, encompassing a variety of mesenchymal tumors with similar histomorphological features, present diagnostic challenges due to their diverse cellular origins and the overlap with other tumor types such as feline sarcoid. This study aimed to delineate the clinical, histomorphological, and immunohistochemical characteristics of 34 feline facial spindle cell tumors affecting 29 cats, including testing for bovine papillomavirus type 14 (BPV14), the virus causing feline sarcoids. Only five out of 12 tumors previously diagnosed as feline sarcoids based on histomorphology were confirmed by PCR for BPV14, underscoring the importance of comprehensive diagnostic approaches to accurately distinguish between STSs and feline sarcoids. This study shows that most facial spindle cell tumors were compatible with peripheral nerve sheath tumors (PNSTs) based on positive immunohistochemical staining for Sox10 and other immunohistochemical markers such as GFAP, NSE, and S100. Some of these tumors displayed as multiple independent masses on the face or as erosive and ulcerative lesions without obvious mass formation, an atypical presentation and an important highlight for general practitioners, dermatologists, and oncologists. This study also describes periadnexal whorling of neoplastic cells as a novel histomorphologic finding in feline facial PNSTs and emphasizes Sox10 as a useful complementary immunohistochemical marker for the diagnosis of facial PNST in cats, providing valuable insights for veterinary pathologists.

Angioleiomyoma of the Ankle: Case Report and Literature Review of a Rare Benign Soft Tissue Tumor

Angioleiomyoma is a benign soft tissue tumor originating in the smooth muscle of blood vessels. It most frequently presents as a painful, free-moving subcutaneous nodule in the lower extremities and is most common in middle-aged women. Angioleiomyoma is rare amongst benign foot neoplasms, and a preoperative diagnosis of angioleiomyoma is rare. We present a case of angioleiomyoma involving the ankle of a 28-year-old female. To prevent patient suffering, we emphasize the importance of an early and accurate diagnosis. Furthermore, we highlight the salient features of angioleiomyoma, which help with the early detection and differentiation of similar malignant variants, including leiomyosarcoma.

Spindle cell neoplasms with novel LTK fusion - Expanding the spectrum of kinase fusion-positive soft tissue tumors

AIMS

Kinase fusion-positive soft tissue tumors represent an emerging, molecularly defined group of mesenchymal tumors with a wide morphologic spectrum and diverse activating kinases. Here, we present two cases of soft tissue tumors with novel LTK fusions.

METHODS AND RESULTS

Both cases presented as acral skin nodules (big toe and middle finger) in pediatric patients (17-year-old girl and 2-year-old boy). The tumors measured 2 and 3 cm in greatest dimension. Histologically, both cases exhibited bland-looking spindle cells infiltrating adipose tissue and accompanied by collagenous stroma. One case additionally displayed perivascular hyalinization and band-like stromal collagen. Both cases exhibited focal S100 staining, and one case had patchy coexpression of CD34. Targeted RNA-seq revealed the presence of novel in-frame MYH9::LTK and MYH10::LTK fusions, resulting in upregulation of LTK expression. Of interest, DNA methylation-based unsupervised clustering analysis in one case showed that the tumor clustered with dermatofibrosarcoma protuberans (DFSP). One tumor was excised with amputation with no local recurrence or distant metastasis at 18-month follow-up. The other case was initially marginally excised with local recurrence after one year, followed by wide local excision, with no evidence of disease at 10 years of follow-up.

CONCLUSIONS

This is the first reported case series of soft tissue tumors harboring LTK fusion, expanding the molecular landscape of soft tissue tumors driven by activating kinase fusions. Furthermore, studies involving a larger number of cases and integrated genomic analyses will be warranted to fully elucidate the pathogenesis and classification of these tumors.

An integrative morpho-molecular approach in malignant ectomesenchymoma diagnosis: report of a new paediatric case and a review of the literature

Introduction

Malignant ectomesenchymoma (MEM) is a soft tissue tumour, consisting of both malignant neuroectodermal elements and one or more mesenchymal elements.

Case presentation and review of the literature

Here we describe the case of a 6-months-old male, previously treated in another hospital for abdominal rhabdomyosarcoma (RMS). Histological re-examination demonstrated that the tumour had mesenchymal and neuroectodermal elements components, with a new diagnosis of abdominal-pelvic MEM. A Next-Generation Sequencing (NGS) analysis was performed on a surgical tumour specimen and revealed the presence of a somatic mutation, already reported in MEM cases. We carried out a review of the literature and we found 33 new cases of MEM since the last review. We reported the clinic-pathologic features of new cases of MEM, highlighting the role of molecular studies in supporting the diagnosis of this ambiguous tumours.

Conclusion

We promote the importance of a diagnosis based on an integrative morpho-molecular approach, that routinely include molecular analysis and the use of bioinformatic mutation detection tools, to support diagnostic and therapeutical queries and to highlight tumour biology and behaviour.

Ossifying fasciitis of the proximal lower extremity

Ossifying fasciitis is a rare benign tumor of heterotopic bone formation within fascial tissue. We present a case of a 23-year-old female with a nontraumatic painful mass of the left proximal thigh identified as ossifying fasciitis, a lesion that must be considered in the differential diagnosis of soft tissue tumors.

Ancient Schwannoma of the Thigh: Metaplastic Ossification, Cartilage Formation, and Extensive Calcification

Benign soft tissue masses that present with atypical features on imaging may erroneously be diagnosed as malignant processes. An ancient schwannoma, a schwannoma variant with pronounced degenerative features, is one possible etiology of an incidental soft tissue tumor. This case report describes a 69-year-old male with a history of lung carcinosarcoma who presented to the orthopedic oncology office following an incidental positron emission tomography-computed tomography (PET-CT) finding of a posterior, lateral thigh mass with extensive calcifications. Subsequent excision and pathological analysis revealed an ancient schwannoma with advanced degenerative features, including metaplastic bone and cartilage formation. Various degenerative changes may typically be identified with pathological analysis. In addition to the degenerative findings on pathological analysis, our case highlights an atypical instance where extensive calcification and ossification are evident radiographically. This case emphasizes the importance of considering ancient schwannoma when a calcified soft tissue mass is encountered, in addition to the list of more common calcified soft tissue masses.

Outcomes and complications of postoperative seroma cavities following soft-tissue sarcoma resection

Introduction

Seroma development is a known complication following extremity and trunk soft-tissue sarcoma (STS) resection. The purpose of this study is to evaluate and characterize seroma outcomes and the development of associated complications.

Methods

A retrospective review of 123 patients who developed postoperative seromas following STS resection at a single institution was performed. Various patient and surgical factors were analyzed to determine their effect on overall seroma outcomes.

Results

77/123 seromas (62.6%) were uncomplicated, 30/123 (24.4%) developed infection, and 16/123 (13.0%) were symptomatic and required aspiration or drainage for symptom relief at an average of 12.2 months postoperatively. 65/123 (52.8%) seromas resolved spontaneously at an average time of 12.41 months. Seromas in the lower extremity (p=0.028), surgical resection volume >864 cm3, (p=<0.001) and initial seroma volume >42 cm3 (p=<0.001) increased the likelihood of infection. 90% of infected seromas developed the infection within the first three months following initial resection. No seromas which were aspirated or drained ultimately developed an infection following these procedures, though 50% recurred.

Discussion

Most seromas following STS resection are uncomplicated and do not require intervention, though a large resection cavity >864 cm3 and a large seroma volume >42 cm3 are risk factors for complications.

Myopericytoma in an Infant-Imaging Characteristics of a Rare but Benign Entity

Teaching point: Myopericytoma is a rare soft tissue tumor but should be considered in the differential diagnosis of infants with a fast-growing perivascular tumor.

Complementary value of molecular analysis to expert review in refining classification of uncommon soft tissue tumors

The classification of many soft tissue tumors remains subjective due their rarity, significant overlap in microscopic features and often a non-specific immunohistochemical (IHC) profile. The application of molecular genetic tools, which leverage the underlying molecular pathogenesis of these neoplasms, have considerably improved the diagnostic abilities of pathologists and refined classification based on objective molecular markers. In this study, we describe the results of an international collaboration conducted over a 3-year period, assessing the added diagnostic value of applying molecular genetics to sarcoma expert pathologic review in a selected series of 84 uncommon, mostly unclassifiable mesenchymal tumors, 74 of which originated in soft tissues and 10 in bone. The case mix (71% historical, 29% contemporary) included mostly unusual and challenging soft tissue tumors, which remained unclassified even with the benefit of expert review and routine ancillary methods, including broad IHC panels and a limited number of commercially available fluorescence in situ hybridization (FISH) probes. All cases were further tested by FISH using a wide range of custom bacterial artificial chromosome probes covering most of known fusions in sarcomas, whereas targeted RNA sequencing was performed in 13 cases negative by FISH, for potential discovery of novel fusion genes. Tumor-defining molecular alterations were found in 48/84 tumors (57%). In 27 (32%) cases the tumor diagnosis was refined or revised by the additional molecular work-up, including five cases (6%), in which the updated diagnosis had clinical implications. Sarcoma classification is rapidly evolving due to an increased molecular characterization of these neoplasms, so unsurprisingly 17% of the tumors in this series harbored abnormalities only very recently described as defining novel molecularly defined soft tissue tumor subsets.

Osteosarcomas With Few Chromosomal Alterations or Adult Onset Are Genetically Heterogeneous

Osteosarcoma is the most common primary bone malignancy, often detected in children and adolescents and commonly associated with TP53 alterations along with a high number of chromosomal rearrangements. However, osteosarcoma can affect patients of any age, and some tumors display less genetic complexity. Besides TP53 variants, data on key driving mutations are lacking for many osteosarcomas, particularly those affecting adults. To detect osteosarcoma-specific alterations, we screened transcriptomic and genomic sequencing and copy number data from 150 bone tumors originally diagnosed as osteosarcomas. To increase the precision in gene fusion detection, we developed a bioinformatic tool denoted as NAFuse, which extracts gene fusions that are verified at both the genomic and transcriptomic levels. Apart from the already reported genetic subgroups of osteosarcoma with TP53 structural variants, or MDM2 and/or CDK4 amplification, we did not identify any recurrent genetic driver that signifies the remaining cases. Among the plethora of mutations identified, we found genetic alterations characteristic of, or similar to, those of other bone and soft tissue tumors in 8 cases. These mutations were found in tumors with relatively few other genetic alterations or in adults. Due to the lack of clinical context and available tissue, we can question the diagnosis only on a genetic basis. However, our findings support the notion that osteosarcomas with few chromosomal alterations or adult onset seem genetically distinct from conventional osteosarcomas of children and adolescents.

MRI T2 mapping assessment of T2 relaxation time in desmoid tumors as a quantitative imaging biomarker of tumor response: preliminary results

Objectives

Because size-based imaging criteria poorly capture biologic response in desmoid-type fibromatosis (DF), changes in MRI T2 signal intensity are frequently used as a response surrogate, but remain qualitative. We hypothesized that absolute quantification of DF T2 relaxation time derived from parametric T2 maps would be a feasible and effective imaging biomarker of disease activity.

Methods

This IRB-approved retrospective study included 11 patients with DF, managed by observation or systemic therapy, assessed by 3T MRI. Tumor maximum diameter, volume, and T2-weighted signal intensity were derived from manual tumor segmentations. Tumor:muscle T2 signal ratios were recorded. Two readers measured tumor T2 relaxation times using a commercial T2 scanning sequence, manual ROI delineation and commercial calculation software enabling estimation of reader reliability. Objective response rates based on RECIST1.1 and best responses were compared between size-based and signal-based parameters.

Results

Median patient age was 52.6 years; 8 subjects were female (73%). Nine patients with longitudinal assessments were followed for an average of 314 days. Median baseline tumor diameter was 7.2 cm (range 4.4 - 18.2 cm). Median baseline T2 was 65.1 ms (range 40.4 - 94.8 ms, n=11); median at last follow-up was 44.3 ms (-32% from baseline; range 29.3 - 94.7 ms, n=9). T2 relaxation times correlated with tumor:muscle T2 signal ratios, Spearman p=0.78 (p<0.001). T2 mapping showed high inter-reader reliability, ICC=0.84. The best response as a percentage change in T2 values was statistically significant (mean -17.9%, p=0.05, paired t-test) while change in diameter was not (mean -8.9%, p=0.12).

Conclusions

Analysis of T2 relaxation time maps of DF may offer a feasible quantitative biomarker for assessing the extent of response to treatment. This approach may have high inter-reader reliability.

Rare Intramuscular Myxoma Involving the Pterygoid and Masseteric Muscles: A Case Report

Myxomas, characterized by abundant mucoid stroma and spindle cells, represent a subset of benign soft tissue tumors. Intramuscular myxomas in the maxillofacial region are rare, posing diagnostic challenges. We present the case of a 58-year-old male who reported limited jaw movement. Physical examination revealed asymmetry, restricted mouth opening, and left lateral jaw movement. Imaging confirmed a well-defined myxomatous mass. Core needle biopsy confirmed an intramuscular myxoma involving the pterygoid and masseteric muscles. A multidisciplinary team opted for surveillance due to its benign nature. Follow-up at six months showed stable findings, supporting the decision for non-surgical management. This case highlights the diagnostic and management challenges of rare intramuscular myxomas in the maxillofacial region. A comprehensive diagnostic work-up, including clinical, radiological, and histopathological data, is crucial. Non-surgical management, guided by a benign nature, underscores the importance of judicious and multidisciplinary approaches. Regular follow-up contributes to understanding the natural history of intramuscular myxomas, emphasizing the need for vigilant monitoring in soft tissue tumor management.

Complications of cryoprobe cryoablation as a surgical adjuvant for the treatment of metastatic carcinoma to bone, benign bone tumors, and soft tissue tumors: A series of 148 patients

BACKGROUND AND OBJECTIVE

This study describes the complication profile of modern cryoablation utilizing probes as an adjuvant during open surgical treatment of orthopedic tumors.

METHODS

A retrospective, single-surgeon study was performed for patients receiving cryoprobe cryoablation. Demographic information, malignancy-related and operative details, and clinical courses were collected. Outcomes assessed included rates of complications, recurrence, and correlations between the number of probes or cryoablation cycles performed.

RESULTS

In this 148-patient study, 67.6% had metastatic carcinoma to bone, 27.7% had benign bone tumors, and 4.7% had soft tissue tumors. An average of 3.4 ± 1.7 cryoablation probes were utilized and 1.7 ± 0.6 freezing cycles were performed. The overall cohort aggregate complication rate was 16.9%. These complications included postoperative fracture (3.4%), nerve palsy (2.7%), wound complications (7.4%), and infection (3.4%). The number of cycles and probes was significantly correlated with the incidence of aggregate complications in the overall cohort (Pearson = 0.162, p = 0.049) and metastatic bone cohort (Pearson = 0.222, p = 0.027). There were 13 recurrences.

CONCLUSION

This study describes the complication rates involving cryoablation probes used as surgical adjuvants. Greater probe number usage was correlated with increased aggregate complications in patients with metastatic disease to bone; meanwhile, more treatment cycles were associated with increased aggregate complications in the overall cohort.

Massive Localized Abdominal Lymphedema: A Case Report with Literature Review

Massive localized lymphedema (MLL) is a rare disease caused by the obstruction of lymphatic vessels with specific clinical morphological and radiological characteristics. People with morbid obesity are mainly affected by MLL. Lymphedema is easily confused with soft tissue sarcoma and requires differential diagnosis, both the possibility of an MLL and also carcinoma manifestations in the soft tissues. The possible causes of massive lymphedema include trauma, surgery, and hypothyroidism. This report is the first case of MLL treated surgically in the Russian Federation. Detailed computed tomography (CT) characteristics and an electron microscope picture of MLL are discussed. A 50-year-old woman (body mass index of 43 kg/m 2 ) with MLL arising from the anterior abdominal wall was admitted to the hospital for surgical treatment. Its mass was 22.16 kg. A morphological study of the resected mass confirmed the diagnosis of MLL. We review etiology, clinical presentation, diagnosis, and treatment of MLL. We also performed an electron-microscopic study that revealed interstitial Cajal-like cells telocytes not previously described in MLL cases. We did not find similar findings in the literature. It is possible that the conduction of an ultrastructural examination of MLL tissue samples will further contribute to the understanding of MLL pathogenesis.

Diagnostic Superiority of Dual-Time Point [18F]FDG PET/CT to Differentiate Malignant from Benign Soft Tissue Tumors

[18F]FDG PET/CT is used in the workup of indeterminate soft tissue tumors (STTs) but lacks accuracy in the detection of malignant STTs. The aim of this study is to evaluate whether dual-time point [18F]FDG PET/CT imaging (DTPI) can be useful in this indication. In this prospective study, [18F]FDG PET/CT imaging was performed 1 h (t1) and 3 h (t2) after injection. Tumor uptake (SUVmax) was calculated at each time point to define a retention index (RI) corresponding to the variation between t1 and t2 (%). Sixty-eight patients were included, representing 20 benign and 48 malignant tumors (including 40 sarcomas). The RI was significantly higher in malignant STTs than in benign STTs (median: +21.8% vs. -2%, p < 0.001). An RI of >14.3% predicted STT malignancy with a specificity (Sp) of 90% and a sensitivity (Se) of 69%. An SUVmaxt1 of >4.5 was less accurate with an Sp of 80% and an Se of 60%. In a subgroup of tumors with at least mild [18F]FDG uptake (SUVmax ≥ 3; n = 46), the RI significantly outperformed the diagnostic accuracy of SUVmax (AUC: 0.88 vs. 0.68, p = 0.01). DTPI identifies malignant STT tumors with high specificity and outperforms the diagnostic accuracy of standard PET/CT.

Practical approach to ultrasound of soft tissue tumors and the added value of MRI: how I do it

This review outlines a practical approach to the everyday assessment of both non-neoplastic and neoplastic soft tissue tumors, focusing on ultrasound examination, though emphasizing the added benefit of magnetic resonance imaging in certain instances. Ultrasound approach and assessment, practical scenarios, reporting, biopsy, and follow-up are covered, as well as the criteria used to distinguish benign from malignant tumors. The potential benefits and current limitations of elastography and contrast-enhanced ultrasound in assessment are also addressed. Examples of commonly encountered soft tissue tumors are shown. Ultrasound can characterize most soft tissue masses based on their ultrasound appearance alone. Following ultrasound examination, three potential scenarios usually exist in clinical practice: (a) confident regarding diagnosis, (b) indeterminate mass with no evidence of malignancy, and (c) indeterminate mass with possibility of malignancy. A diagnostic pathway for each of these scenarios is provided. Magnetic resonance imaging is generally not helpful in further characterizing masses which are indeterminate on ultrasound assessment, though it is helpful in addressing other issues such as exact tumor location and neurovascular bundle involvement that may not be fully resolved on ultrasound examination. In these situations, magnetic resonance imaging examination can be tailored to address those specific questions that have not been adequately addressed on ultrasound examination. In this sense, both examinations are highly complementary. Tips for undertaking magnetic resonance imaging examinations are provided.

Treatment of malignant perivascular epithelioid cell tumor (PEComa) on the knee with an anterolateral thigh free flap: A case report

RATIONALE

The World Health Organization defines a perivascular epithelioid cell tumor (PEComa) as a mesenchymal neoplasia composed of perivascular epithelioid cells with characteristic morphological and immunohistochemical features. Although PEComas have the potential to behave in a malignant fashion, malignant PEComas are extremely rare.

PATIENT CONCERNS

An 83-year-old man visited our clinic presented with palpable, painless, and movable mass in the right knee area.

DIAGNOSES

Malignant PEComa was diagnosed by incisional biopsy. No metastases was confirmed by radiologic imaging including PET/CT, magnetic resonance imaging, high resolution computed tomography.

INTERVENTIONS

We performed wide excision of the mass and used an anterolateral thigh free flap to reconstruct the defect on the right knee.

OUTCOMES

The permanent histopathology showed malignant PEComa was totally resected. The flap which was performed to cover the defect was survived and the patient discharge without any complications.

LESSONS

PEComa can metastasize to various anatomical regions. Although there is no established standardized treatment, radical resection is still considered the cornerstone of treatment. Rapid and appropriate defect coverage is important to improve the patient's prognosis.

Detection of various fusion genes by one-step RT-PCR and the association with clinicopathological features in 242 cases of soft tissue tumor

Introduction: Over the past decades, an increasing number of chromosomal translocations have been found in different STSs, which not only has value for clinical diagnosis but also suggests the pathogenesis of STS. Fusion genes can be detected by FISH, RT-PCR, and next-generation sequencing. One-step RT-PCR is a convenient method to detect fusion genes with higher sensitivity and lower cost. Method: In this study, 242 cases of soft tissue tumors were included, which were detected by one-step RT-PCR in multicenter with seven types of tumors: rhabdomyosarcoma (RMS), peripheral primitive neuroectodermal tumor (pPNET), synovial sarcoma (SS), myxoid liposarcomas (MLPS), alveolar soft part sarcoma (ASPS), dermatofibrosarcoma protuberans (DFSP), and soft tissue angiofibroma (AFST). 18 cases detected by one-step RT-PCR were further tested by FISH. One case with novel fusion gene detected by RNA-sequencing was further validated by one-step RT-PCR. Results: The total positive rate of fusion genes was 60% (133/213) in the 242 samples detected by one-step RT-PCR, in which 29 samples could not be evaluated because of poor RNA quality. The positive rate of PAX3-FOXO1 was 88.6% (31/35) in alveolar rhabdomyosarcoma, EWSR1-FLI1 was 63% (17/27) in pPNET, SYT-SSX was 95.4% in SS (62/65), ASPSCR1-TFE3 was 100% in ASPS (10/10), FUS-DDIT3 was 80% in MLPS (4/5), and COL1A1-PDGFB was 66.7% in DFSP (8/12). For clinicopathological parameters, fusion gene status was correlated with age and location in 213 cases. The PAX3-FOXO1 fusion gene status was correlated with lymph node metastasis and distant metastasis in RMS. Furthermore, RMS patients with positive PAX3-FOXO1 fusion gene had a significantly shorter overall survival time than those patients with the negative fusion gene. Among them, the FISH result of 18 cases was concordant with one-step RT-PCR. As detected as the most common fusion types of AHRR-NCOA2 in one case of AFST were detected as negative by one-step RT-PCR. RNA-sequencing was used to determine the fusion genes, and a novel fusion gene PTCH1-PLAG1 was found. Moreover, the fusion gene was confirmed by one-step RT-PCR. Conclusion: Our study indicates that one-step RT-PCR displays a reliable tool to detect fusion genes with the advantage of high accuracy and low cost. Moreover, it is a great tool to identify novel fusion genes. Overall, it provides useful information for molecular pathological diagnosis and improves the diagnosis rate of STSs.

Giant anterior abdominal wall desmoid tumor successfully managed with abdominal wall reconstruction

Anterior abdominal wall fibromatosis is a benign soft tissue tumor that is rare, but fast-growing with minimal chances of malignant change. We report a young female with a large abdominal swelling which on evaluation was provisionally diagnosed as anterior abdominal wall fibromatosis on imaging and confirmed by histopathology. She was successfully managed with resection of the tumor with a challenging abdominal wall reconstruction with bilateral inferiorly based external oblique muscle flap followed by a mesh repair. Though rare, these tumors are difficult to miss. The importance of this case report is that it describes the methods of multimodal management of a patient with surgery, reconstruction, and adjuvant therapy leading to better patient outcomes.

[Giant myoepithelial carcinoma of the nuchal region: a case report and literature review]

Myoepithelioma, also known as malignant myoepithelioma, is a rare malignant tumor originating from myoepithelial cell. This article reports a patient with a huge tumor in the neck and left elbow who underwent fine needle aspiration under local anesthesia. The pathological diagnosis was a myoepithelioma. Under general anesthesia, giant tumors in the lower neck, posterior cranial fossa, neck, and left elbow were removed, and postoperative pathology showed that they were all myoepithelial tumors. Immunohistochemistry showed AE1/AE3 (+), P63 (+), CK7 (+), CK5 (+), and CD138 (+). The clinical characteristics and diagnosis and treatment process of this case are reported and relevant literature is reviewed.

Leiomyosarcoma Originating From Axilla in Neurofibromatosis Type 1: A Rare Occurrence

Neurofibromatosis type 1 (NF1) or von Recklinghausen syndrome is an autosomal dominant disorder that affects the multisystem in the body with complex presentation caused by the neurofibromin gene mutation on chromosome 17. These patients tend to develop soft tissue sarcomas more than the general population. Leiomyosarcoma is a malignant soft tissue tumor that may occur in patients with NF1 in rare cases. We present a case of a rare development of leiomyosarcoma in a 45-year-old female patient with a history of NF1. She developed a progressively growing mass in the left axilla associated with numerous neurofibromas and axillary freckling. MRI revealed a heterogeneous large mixed signal intensity mass in the left axilla, and the diagnosis was confirmed through biopsy.

Can a diagnosis of Leiomyosarcoma soft palate be missed in the era of commoner oral carcinomas? - Rare case report and review of literature

Leiomyosarcomas (LMSs) of the head and neck are an extremely rare entity. Of all smooth muscle tumors, 4%-10% occur in the head and neck and only 0.06% in the oral cavity. Because of its infrequency, it has been associated with both delayed diagnosis and misdiagnosis. Here, we report the clinicopathological findings of a case of primary LMS of the soft palate in a 42-year-old male patient with an emphasis on the judicious use of ancillary diagnostic modalities to arrive at a definitive diagnosis. Intraorally, LMSs present as painless, lobulated, fixed masses of the submucosal tissues in middle-aged or older individuals. The treatment modalities and lymph nodal dissection criteria are dissimilar to more common oral carcinomas. Hence, definitive diagnosis is necessary.

Soft Tissue Tumor Without Neurofibromatosis Type 1 With Histopathological Suspicion of Atypical Neurofibromatous Neoplasm of Uncertain Biological Potential (ANNUBP)

Atypical neurofibromatous neoplasm of uncertain biological potential (ANNUBP), defined as a borderline lesion that is difficult to distinguish whether benign or malignant, is one of the intermediate stages to malignant peripheral nerve sheath tumor, a peripheral nerve-derived malignant tumor that develops from nerve sheath cells. Because ANNUBP is a new concept, only a few cases have been reported, all in patients with neurofibromatosis type 1 (NF-1).An 88-year-old woman presented with a mass on the left upper arm persisting for one year. Magnetic resonance imaging showed a large tumor spreading between the humerus and biceps muscle, which was diagnosed as undifferentiated pleomorphic sarcoma by needle biopsy. Extensive tumor resection was performed, including partial cortical bone resection of the humerus. Based on the histological features, although the patient did not have NF-1, the tumor was strongly suspected to be ANNUBP. As malignant peripheral nerve sheath tumors have been sporadically reported in patients without NF-1, it is feasible that ANNUBP could also occur in patients without NF-1.

The Recent Advances in Molecular Diagnosis of Soft Tissue Tumors

Soft tissue tumors are rare mesenchymal tumors with divergent differentiation. The diagnosis of soft tissue tumors is challenging for pathologists owing to the diversity of tumor types and histological overlap among the tumor entities. Present-day understanding of the molecular pathogenesis of soft tissue tumors has rapidly increased with the development of molecular genetic techniques (e.g., next-generation sequencing). Additionally, immunohistochemical markers that serve as surrogate markers for recurrent translocations in soft tissue tumors have been developed. This review aims to provide an update on recently described molecular findings and relevant novel immunohistochemical markers in selected soft tissue tumors.

Solitary Fibrous Tumor of the Peritoneal Cavity and Greater Omentum: Case Report and Review of the Literature

Background

The solitary fibrous tumor is a rare soft tissue mesenchymal tumor which typically arises from the pleura but may be found anywhere in the body. Abdominal localizations are very rare. The solitary fibrous tumor is classified into two forms, pleural and extrapleural, and morphologically they resemble each other. The diagnostics of the tumor is usually accidental because usually there are no clinical symptoms. The main treatment of the solitary fibrous tumor is the surgical removal of the tumor while radiotherapy treatment and chemotherapy outcomes remain unclear due to the rarity of the tumor and lack of data.

Case presentation

We report the case of the 32-year-old man who was diagnosed with the solitary fibrous tumor of the peritoneal cavity. Laparotomy was performed. A grayish-white, stiff, coarse-grained tumor about 11 cm in diameter of the greater omentum was found and radical omentectomy with tumor removal were performed. Postoperative course was uneventful and the patient is well with no signs of recurrence on the CT scan of the chest and abdomen and MRI of the pelvis at 6 months after surgery.

Conclusions

The solitary fibrous tumor is a rare condition. It is a borderline-malignant tumor but may cause serious complications if not treated. Due to the absence of clinical symptoms, the tumor is usually detected accidentally. The radical surgical removal of the tumor is the most optimal treatment.

Adipose and lipoma stem cells: A donor-matched comparison

Lipomas are slow growing benign fat tumors that develop in soft tissues of the mesoderm. Thus, the specific (dys-)function of mesenchymal stem cells (MSCs) has been suggested in the development of lipomas, but details of the tumor pathogenesis remain unclear. Existing studies comparing stem cells from native adipose (adipose stem cells [ASCs]) and lipomatous tissues (LSCs) have reported contradicting findings. However, harvesting ASCs and LSCs from different individuals might have influenced proper comparison. Therefore, we aimed to characterize donor-matched ASCs and LSCs to investigate metabolic activity, proliferation, capability for tri-linear differentiation (chondrogenesis, adipogenesis, osteogenesis), and the secretome of mature adipocytes and lipomacytes. Both stem cell types did not differ in metabolic activity, but ASCs demonstrated stronger proliferation than LSCs. While there was no difference in proteoglycan accumulation during chondrogenic differentiation, adipogenesis was higher in ASCs, with more lipid vacuole formation. Conversely, LSCs showed increased osteogenesis by higher calcium deposition. Lipomacytes showed stronger secretory activity and released higher levels of certain adipokines. Our findings indicated that LSCs possessed important characteristics of MSCs, including ASCs. However, LSCs' low proliferation and adipogenic differentiation behavior did not appear to account for enhanced tissue proliferation, but the secretome of lipomacytes could contribute to lipomatous neoplasm.

Childhood proliferative fasciitis of the orbit mimicking sarcoma: a case report

Proliferative fasciitis (PF) is a benign fibroblastic reaction with histological and clinical characteristics that overlap with those of malignant soft tissue tumors; thus, it is referred to as a pseudosarcomatous reaction. It continues to be an important cause of diagnostic error and overtreatment. The childhood PF subtype has some distinct histological and immunohistochemical characteristics that make differential diagnosis with malignant tumors even harder, especially with sarcoma. These proliferations generally occur in the lower limbs, and the periorbital region is a rare location of appearance. Here, we describe a case of childhood subtype PF in a 16-year-old girl located in the periorbital area. To the best of our knowledge, this is the first reported case of childhood subtype PF in the periorbital area, and the third case if PF subtypes are not taken into account.

Malignant myopericytoma: Case report and review of the literature

A 29-year-old male presented with a two-week history of a tender lesion on his right thigh. The lesion was a 1.5 cm erythematous nodule with overlying hemorrhagic crust. Histopathologic examination of a biopsy specimen revealed a highly cellular neoplasm with irregular vesicular nuclei, prominent nucleoli, and scattered mitotic figures. The cells within the lesion were rounded, ovoid and spindle shaped cells with perivascular growth. The architecture and staining pattern of the lesion were most consistent with a diagnosis of malignant myopericytoma, an exceedingly rare malignancy.

Performance of Machine Learning Methods Based on Multi-Sequence Textural Parameters Using Magnetic Resonance Imaging and Clinical Information to Differentiate Malignant and Benign Soft Tissue Tumors

RATIONALE AND OBJECTIVES

To evaluate the performance of a machine learning method to differentiate malignant from benign soft tissue tumors based on textural features on multiparametric magnetic resonance imaging (mpMRI).

MATERIALS AND METHODS

We enrolled 163 patients with soft tissue tumors whose diagnosis was pathologically proven (71 malignant, 92 benign). All patients underwent mpMRI. Twelve histographic and textural parameters were assessed on T1-weighted imaging (T1WI), T2-weighted imaging, diffusion-weighted imaging, apparent diffusion coefficient maps, and contrast-enhanced T1WI imaging. We compared mean signals of all sequences from the malignant and benign tumors using Welch's t-test. Prediction models were developed via a machine learning technique (support vector machine) using textural features of each sequence, clinical information (sex + age + tumor size), and the combined model incorporating all features. Areas under the receiver operating characteristic curves (AUCs) of these models were calculated using fivefold cross validation.

RESULTS

The diagnostic ability of clinical information model (AUC 0.85) was not inferior to the model with textural features of each sequence (AUC 0.79-0.84). The combined model showed the highest diagnostic ability (AUC 0.89). The AUC of the combined model (0.89) was comparable to those of two board-certified radiologists (0.89 and 0.87).

CONCLUSIONS

Machine learning methods based on textural features on mpMRI and clinical information offer adequate diagnostic performance to differentiate between malignant and benign soft tissue tumors.

Primary Retroperitoneal Smooth Muscle Tumor of Uncertain Malignant Potential (STUMP): A Diagnostic Enigma

Retroperitoneal sarcomas represent a group of rare malignant neoplasms with complex clinical management and often a poor prognosis. An elderly male presented with a slowly progressive, right-sided abdominal lump for four months associated with loss of appetite and abdominal discomfort. Abdominal examination revealed an apparent retroperitoneal lump in the right lumbar and umbilical region, which was well-defined, and firm in consistency with the bosselated surface. Contrast-enhanced computed tomography (CECT) of the abdomen and pelvis revealed a heterogenous lobulated malignant appearing retroperitoneal lesion arising from the right anterior perirenal space with a differential of retroperitoneal sarcoma. Wide local excision of the tumor was done. Histopathology of the lesion revealed a smooth muscle tumor of uncertain malignant potential (STUMP). The patient is asymptomatic and recurrence-free after 24 months of follow-up.

Rhabdomyosarcoma or Fibrosarcoma? A Case of Large Ulcerated and Necrotic Lesion on the Forearm of a Newborn

Congenital infantile fibrosarcoma (CIFS) is a rare malignant soft tissue tumor. The incidence of fibrosarcoma is estimated to be 0.3 per 100 000 population per year, and it accounts for less than 1% of all soft tissue sarcomas. We present a case of a 7-day-old newborn with a large ulcerated and necrotic lesion on the left forearm, which was initially misdiagnosed as rhabdomyosarcoma. Magnetic resonance imaging (MRI) revealed a soft tissue mass with cystic components affecting the forearm and distal humerus muscles. Fine-needle biopsy was performed and initially diagnosed as rhabdomyosarcoma but later confirmed as low-grade fibrosarcoma with positive immunostaining for vimentin. The patient underwent a transhumeral amputation with follow-up chemotherapy at a specialized oncology center. This case underscores the importance of interdisciplinary collaboration and specialized care in managing complex medical conditions in infants. Early detection and appropriate management of these tumors are essential for improving outcomes and reducing morbidity and mortality. Despite the rarity of this case, it serves as a reminder of the importance of considering neoplastic lesions in the differential diagnosis of soft tissue masses in newborns.

A huge chest wall angiomatosis with pleural and rib invasion: A case report

RATIONALE

Angiomatosis is a rare non-neoplastic proliferative vascular lesion that typically develops during childhood or adolescence with a female predominance. Management of angiomatosis is challenging because of the manifestation of a wide variety of lesions as well as their invasive and highly recurrent nature.

PATIENT CONCERNS

We report the case of a 74-year-old man who presented with a right lower back mass that persisted for a decade. The mass progressively enlarged and had been painful in the previous month.

DIAGNOSIS

Computed tomography (CT) revealed suspected lipomatous sarcoma with invasion of the ribs, pleurae, and lung parenchyma. The final pathological examination revealed angiomatosis.

INTERVENTIONS

The patient underwent wide composite excision of the tumor along with excision of the pleura and lung nodules in the right lower and middle lobes via video-assisted thoracoscopic surgery (VAST). Fasciocutaneous rotational flap reconstruction was performed immediately after the wide composite excision and video-assisted thoracoscopic surgery (VAST).

OUTCOMES

The patient recovered uneventfully, was discharged without complications, and tolerated the daily activities well.

LESSONS

Angiomatosis is a rare benign vascular tumor that frequently mimics malignancy. Even if the patient profile does not match the reported epidemiology of this disease, differential diagnosis should be considered. Complete resection is the mainstay of treatment for the prevention of recurrence.

Extraosseous osteochondroma of superficial fascia layer of the heel: A case report and review of literature

RATIONALE

Osteochondroma is a common benign bone tumor consisting of cartilage-covered bone confluent with the medullary canal of the epiphysis. Extraosseous osteochondroma shares the same appearance and histologic features as a typical osteochondroma but does not have any attachment to surrounding bone structures. Because of its low incidence, extraosseous osteochondroma is uncommon in clinical workups and thus prone to misdiagnosis. The diagnosis of extraosseous osteochondroma should be considered when there is a well-defined bony mass in the soft tissue with no direct continuity with the adjacent bone or joint. Here, we present a case of an imaging diagnosis of "calcified bursitis in the subcutaneous superficial fascial layer" and a postoperative pathological diagnosis of "extraosseous osteochondroma."

PATIENT CONCERNS

The patient was a 61-year-old man who had a right plantar heel mass for 2 years and recently visited the hospital because of discomfort in shoes.

DIAGNOSES

The patient was diagnosed with pathological examination.

INTERVENTIONS

After completing the relevant preoperative examination and preoperative preparation and excluding contraindications to surgery, surgery was performed under nerve block anesthesia.

OUTCOMES

We performed surgical resection, and the patient did not have obvious discomfort when discharged from the hospital. Auxiliary examination showed no abnormalities.

LESSONS

For foot tumors, we need to consider the possibility of extraosseous osteochondroma. After completing the auxiliary examination, we should determine the relationship between the tumor and its surrounding tissues and blood supply before surgery to avoid causing major trauma.

Lipomembranous fat necrosis: A distinctive and unique morphology (Review)

Lipomembranous fat necrosis (LFN) is an uncommon but distinct form of fat necrosis, which is characterized by eosinophilic, crenulated and/or serpiginous membranes. LFN exhibits macrocystic, microcystic and/or crushed features. LFN is routinely detectable on hematoxylin and eosin (H&E)-stained sections, and is present both in the acute phase and in the later or fibrous stage of necrotic fatty lesions. Smaller crushed LFN embedded within fibrous tissues may be difficult to recognize on H&E-stained sections, but can be highlighted by some staining techniques, including Masson trichrome, periodic acid-Schiff, orcein, long Ziehl-Neelsen stain, silver impregnation, phosphotungstic acid-hematoxylin and luxol fast blue staining. LFN was initially considered a specific feature of Nasu-Hakola disease, but has since been identified in various subcutaneous or intraabdominal lesions related to ischemic conditions or venous insufficiency. In addition, LFN is detectable in intra-articular loose bodies and aortic valves with or without dysfunction, suggesting that LFN is also associated with ischemia-like hypoxic conditions or malnutrition. LFN is considered to be a histological hallmark of hidden ischemic or hypoxic/malnourished conditions in various diseases; however, the exact mechanisms of LFN remain poorly understood. The present review described the clinicopathological features of this interesting, but poorly characterized, condition.

Case report: ALK-rearranged spindle and epithelioid cell neoplasms with S100 and CD34 co-expression: Additional evidence of kinase fusion-positive soft tissue tumors

ALK rearrangements have rarely been reported in S100- and CD34-co-expressing soft tissue neoplasms with lipofibromatosis-like neural tumor (LPFNT) pattern or stromal and perivascular hyalinization, mimicking NTRK-rearranged spindle cell tumors. Here, we reported ALK fusions involving related partner genes in two adult soft tissue tumors with S100 and CD34 co-expression, and conducted a literature review of mesenchymal tumors harboring ALK or other kinase fusions. Case 1 was a 25-year-old female who underwent excision of a soft tissue mass in the anterior thigh region. Morphologically, the tumor was composed of spindle cells adjacent to epithelioid cells embedded in myxedematous and hyalinized stroma, with infiltrative boundary. Spindle cells mixed with inflammatory infiltration resembling inflammatory myofibroblastic tumor (IMT) were seen sporadically. However, brisk mitosis and focal necrosis was also observed, indicating an intermediate-grade sarcoma. In case 2, the left side of the neck of a 34-year-old man was affected. The tumor was composed of monomorphic spindle cells arranged in fascicular growth or patternless pattern, with stromal and perivascular hyalinization. Sparse inflammatory cell infiltration was also observed. Both tumors showed CD34, S100, and ALK-D5F3 immunoreactivity. Next generation sequencing (NGS) test identified a PLEKHH2::ALK fusion in case 1, which was confirmed by RT-PCR and Sanger sequencing, whereas the RT-PCR (ARMS method) test detected an EML4::ALK fusion in case 2. In conclusion, this study expands the morphological and genetic landscape of tumors with S100 and CD34 co-expression harboring kinase fusions, and suggests that kinase fusion-positive mesenchymal neoplasms are becoming an enlarging entity with a variety of morphological patterns.

A rare soft tissue tumor of the big toe: Superficial acral fibromyxoma

Superficial acral fibromyxoma (SAF) is a rare and benign soft tissue tumor that has a predilection to develop in acral sites. Its treatment is surgical excision. Follow-up is recommended due to the risk of recurrence. The purpose of this case is to raise awareness of this recently described neoplasm.

Penile Myointimoma: A Clinicopathologic Study of 4 Tumors

Penile myointimoma is a rare, benign tumor occurring within the corpus spongiosum vasculature of the glans penis. Thus far, there have been twenty-three reported tumors in the literature. We present four additional tumors of this unique myointimal proliferation. Patients ranged in age from 20 to 68 years and presented with a firm mass on the glans penis. All four tumors displayed distinctive morphologic features consisting of a myointimal proliferation with plexiform architecture of bland myofibroblastic cells in a myxoid background in the corpus spongiosum vasculature. Characteristic cytoplasmic immunoreactivity of lesional cells with smooth muscle actin in addition to a desmin positive collarette of native vessel smooth muscle was seen in all four tumors. No disease was reported in any of the patients at last clinical follow-up (9 months to 15 years) after biopsy or excision. Myointimoma is part of a rare group of mesenchymal tumors that has been recently classified by its distinctive location, morphology, and immunohistochemical reactivity. For any nodular, spindle cell lesion of the corpus spongiosum, myointimoma should be included in the differential diagnosis given its unique characteristics and favorable clinical outcome.

Diffusion-weighted MR is useful to assess peripheral nerve invasion of soft tissue tumor

To investigate the feasibility of readout-segmented diffusion-weighted (rsDW) magnetic resonance (MR) in assessing nerve invasion of soft tissue tumor. Forty-four patients with soft tissue mass in upper leg suspected of nerve invasion underwent rsDW MR. Nerve invasion by tumor was rated by 2 radiologists, respectively. Sensitivity and specificity of rsDW MR in identifying nerve invasion were calculated, with operation findings as reference of standard. Apparent diffusion coefficient and fraction of anisotropy of nerve were obtained using DW MR, and then were compared between invaded nerves and noninvasion cases. Inter-reader agreement in using rsDW MR to rate nerve invasion was excellent (kappa = 0.891 ± 0.043, P < 0.001). Sensitivity and specificity of rsDW MR in identifying nerve invasion were 89% and 88%, respectively. Apparent diffusion coefficient was significantly higher in invaded nerves versus normal nerves (1.45 ± 0.67 × 10-3 mm2/s vs 1.39 ± 0.46 × 10-3 mm2/s, P < 0.05). Fraction of anisotropy was significantly lower in invaded nerves versus normal nerves (0.22 ± 0.11 vs 0.37 ± 0.13, P < .05). Readout-segmented DW MR was feasible in assessing sciatic nerve invasion by soft tissue tumor in selected patients.

Epithelioid Sarcoma in the Median Nerve of the Hand: A Case Report

Epithelioid sarcoma of the peripheral nerves is extremely rare. We present a case concerning the median nerve of the right hand in a 35-year-old woman who was treated with radical resection, reconstructive surgery, and chemotherapy. After 2 years of follow-up, there is no evidence of local recurrence or metastatic dissemination.

Pediatric fibromyxoid tumor with PLAG1 fusion: An emerging entity with a novel intracranial location

Translocations involving PLAG1 occur in several tumors, most commonly pleomorphic adenoma and lipoblastoma. Recently, a distinctive soft tissue tumor with a PLAG1 fusion has been reported in the pediatric age group. These are low grade tumors with a fibroblastic or mixed fibroblastic and myxoid morphology but no other lines of differentiation. They are typically immunopositive for desmin and CD34. The partner genes for these tumors have included YWHAZ, EEF1A1, ZFHX4l, CHCHD7, and PCMTD1. We report another case of this fibromyxoid tumor with a PLAG1 fusion, this time with COL3A1 as the partner gene. The fusion placed expression of a full-length PLAG1 protein under the control of the constitutively active COL3A1 promoter. Overexpression of PLAG1 was confirmed by diffusely positive immunostaining for PLAG1. The most novel aspect of this tumor is the intracranial location. Opinion has been divided over whether these tumors are a specific entity, or related to lipoblastoma, since that tumor also typically occurs in soft tissue in the pediatric age group and shows many of the same gene fusions. However, lipoblastoma has never been reported in an intracranial location and, thus, our case provides compelling evidence that this fibromyxoid tumor is indeed a distinct entity.

The Giant Infantile Fibrosarcoma of Fetal Oropharynx and Anterior Neck

Introduction: Infantile fibrosarcoma (IFS) usually arises in the extremities during the first 12 months of life and responds well to surgery. It is unusual in the oropharynx or the prenatal period. Case report: A giant solid mass was first detected in the oropharynx and anterior neck at 24 weeks of gestation by ultrasound and fetal MRI. An EXIT procedure with intrapartum intubation with appropriate supportive therapy was successful. The diagnosis of IFS was made postpartum, and the lesion responded to neoadjuvant chemotherapy. Conclusion: IFS may arise as early as 24 weeks of gestation. In this case, an EXIT procedure allowed postpartum diagnosis with subsequent treatment.

Low-grade fibromyxoid sarcoma in the middle ear as a rare location: a case report

BACKGROUND

Low-grade fibromyxoid sarcoma (LGFMS) is a rare soft tissue tumor with a misleadingly bland histological appearance and fully malignant behavior, typically occurring in the deep soft tissues of the proximal extremities or trunk of young adults. However, no cases of primary middle ear LGFMS have been reported previously. LGFMS is characterized by high rates of local recurrence and metastatic spread, which should be attached of great importance to clinical diagnosis and treatment.

CASE DESCRIPTION

Herein, we report an unusual case of LGFMS occurring primarily in the middle ear of a 12-year-old boy, who presented with aural fullness and gradually progressive hearing loss in the left ear for 6 months, without other related symptoms and family history. Preoperative imaging examination suggested that the lesions were located in the tympanic cavity, tympanic antrum, and mastoid portion, with equisignal or hypointense on T1 weighted image (T1WI), apparent hyperintense on T2 weighted image (T2WI), and slight enhancement on T1WI following administration of gadolinium. A decision was made to perform mastoidectomy, as the lesion was limited to the middle ear and did not invade the facial nerve canal or the inner ear. During the surgery, the mass exhibited a hard texture and smooth surface that was approximately 1.0 cm × 1.5 cm in size, not easy to bleed, and non-adherent to surrounding tissues. After consultation, a diagnosis of LGFMS was made by postoperative pathology. The patient showed an excellent recovery from surgery without any complications. At present, the patient has been followed up for 24 months, and no local recurrence or distant metastasis has been observed.

CONCLUSIONS

The primary LGFMS in the middle ear is very rare, and the clinical manifestations and related examinations lack specificity, so a clinical diagnosis of LGFMS is very difficult, and the final diagnosis is mainly determined by pathological diagnosis. Due to its malignant behavior, clinical diagnosis and treatment should be vigilant against it. Treatment of LGFMS mainly requires extensive resection combined with radiotherapy and chemotherapy if necessary, and long-term follow-up is essential. Reporting and identification of this rare case are imperative to improving our understanding of LGFMS and reducing misdiagnosis.

Extraneuraxial Hemangioblastoma: An Unusual Soft Tissue Neoplasm that Mimics More Common Entities but Carries Distinct Clinical Implications

Hemangioblastoma, one of the characteristic tumors associated with Von Hippel-Lindau (VHL) disease, most often presents in the central nervous system (CNS) but can uncommonly arise in extraneuraxial, or previously referred to as peripheral, locations. Without the clinical context of known VHL disease, hemangioblastoma may not enter the differential for a soft tissue mass outside the CNS. Here, we present two patients with diagnostically challenging extraneuraxial hemangioblastoma to highlight the importance of considering this entity within the differential diagnosis of soft tissue neoplasms containing clear cells and delicate vasculature. We review the relevant diagnostic features, including a suggested immunohistochemical panel, along with the potential associated clinical implications of making this diagnosis. It is recommended that affected patients be offered genetic counseling to assess for underlying VHL disease.

Deep Fat Saving Elevation of the Superficial Circumflex Iliac Artery Perforator Flap

Background and Objectives: Prolonged drain stay and lymphorrhea are often problems at the donor site of the superficial circumflex iliac artery perforator (SCIP) flap. This study aimed to introduce a novel technique of the SCIP flap elevation: Deep Fat Saving (DFS) technique. Materials and Methods: Thirty-two patients who underwent the SCIP flap transfer were divided based on the flap-elevated layer: above the deep fascia or the Camper fascia saving the deep fat. The duration of drain stay and the rates of flap survival and donor-site complications were compared between the groups. The inverse probability weighting (IPW) method was conducted to balance confounders. Results: By IPW, two balanced pseudo-populations were created: DFS = 33.9 and Conventional = 31.3. There were no significant differences in the rate of flap survival (DFS: 100% verses Conventional: 95.8%, p = 0.32) and donor site complications (DFS: 2.4% versus Conventional: 1.3%, p = 0.68, respectively). The duration of drain stay was shorter in the DFS group (weighted median: 6 versus 8 days; weighted difference: -1.6 days (95% confidence interval: -2.8 to -0.4), p = 0.01). Conclusions: An SCIP flap can be reliably harvested using the Deep Fat Saving technique.

Myoepithelioma-like tumors of the vulvar region: A case report and review of the literature

Myoepithelioma-like tumors of the vulvar region (MELTVR) is a kind of solid tumor newly recognized in recent years, which is characterized by mesenchymal tumors of adult female vulva. The histopathology is similar to myoepithelioma, but the immunohistochemical phenotype and genetic changes are different from myoepithelioma. It usually has clear boundary and partial capsule, mixed with two forms of cells (epithelioid and spindle), the cells are mild, the nucleoli are clear, mitoses are rare, some cases have myxoid differentiation. In this article, a case of MELTVR diagnosed in our hospital is discussed. The patient was a 43-year-old female who finds a neoplasm in the pubic tubercle 4 months ago. Local resection was performed. Pathological examination showed that the boundary of the tumor was clear with partial capsule. The cells were arranged in cords or nests, and partially infiltrated the surrounding adipocytes. The tumor cells had two morphologies, epithelioid or spindle shaped. The spindle type cells were dominant, with bright cytoplasm, obvious nucleoli, rare nuclear mitosis (about 1/10HPF), and no necrosis was observed. Immunohistochemically, the tumor cells were positive for vimentin, epithelial membrane antigen, estrogen receptor, progestogen receptor, calponin and were partially positive for cathepsin k. INI1/SMARCB1 expression was deficient. There was no recurrence or metastasis during the 8-month-long follow-up. The unique feature of this case was that the site of the disease was not the vulva, but in front of the pubic tubercle, there was no large amount of mucus production, and the cytoplasm of most tumor cells was transparent. Due to our limited knowledge of MELTVR, its pathogenesis and tissue origin are not clear. Clinicians should be aware of such potential patients.

A microcystic/reticular schwannoma in an unusual site: description of a retroperitoneal location and review of the literature

Microcystic/reticular (MRV) schwannoma has been described since 2008, but remains a rarely encountered entity. MRV has a predilection for visceral locations and has variable histologic appareances. Given its rarity and anatomic variability, this entity could raise differential diagnostic issues with other tumours and malignancies.

We describe the case of a 69-year-old male followed at IRCCS Ospedale Policlinico San Martino of Genoa for his previous history of non-Hodgkin lymphoma. A para-aortic mass was discovered during follow-up, which -due to its stability, also after chemotherapy- had been hypothesized to be a non-lymphomatous lesion; given the dimensions and the site, the mass was removed. Histological evaluation showed a nodule limited by a slight fibrous capsule and characterized by a proliferation of medium-sized fusiform cells, with elongated nuclei and scarce eosinophilic cytoplasm. Given the lack of malignant signs and the strong expression of protein S-100, a diagnosis of mesenchymal neoplasia with expression of neural markers compatible with reticular schwannoma was made. The neoplasm has not recurred since its removal.

The case we present is, at our best knowledge, the first described in the retroperitoneum, a site where the exclusion of other mesenchymal malignancies is mandatory. The rarity and variability of presentations could create problems of differential diagnosis both with mucinous-producing carcinomas or with other soft tissue tumours, with myxoid or reticular structure. The description of this case could help raise information on this rare neoplasm and help distinguish it from other malignancies, especially in unusual sites.

Outcomes of Sarcopenia Treatment for Malignant Bone and Soft Tissue Tumors in Elderly Patients

BACKGROUND/AIM

We determined the impact of sarcopenia on the treatment outcomes of malignant bone and soft tissue tumors in elderly patients.

PATIENTS AND METHODS

We retrospectively reviewed 76 patients (age ≥65 years) who were treated for malignant bone and soft tissue tumors. Sarcopenia was assessed by measuring the cross-sectional area of the psoas muscles at the L3 vertebra from preoperative computed tomography images and categorized using the total psoas area/m ² (TPA/m ² ) ≤5.0 cm ² /m ² . The patients' clinical data were then evaluated.

RESULTS

The operation time, length of hospital stay, and median overall survival were not different between the sarcopenia (n=41) and no-sarcopenia (n=35) groups. The local recurrence rate (p=0.01) and incidence of postoperative complications (p=0.02) significantly differed between both groups. The TPA/m ²  of both groups significantly decreased at the final follow-up.

CONCLUSION

Sarcopenia negatively influenced wound healing and local recurrence, and was significantly exacerbated postoperatively in all elderly patients.

Prevalence of elastofibroma dorsi found incidentally upon chest computed tomography scan: A tertiary care center experience

Objectives:

To determine the prevalence and demographic data regarding incidentally encountered elastofibroma dorsi (EFD) in the Saudi population-based on chest CT (computed tomography) scans.

Methods:

This retrospective study was carried out on 4,435 chest CT examinations that were collected between January 2014 and December 2016 in Riyadh, Saudi Arabia. One musculoskeletal radiologist who was unaware of the patients’ clinical presentations or reasons for CT study reviewed the 4,435 chest CTs prospectively, searching for soft tissue tumors in the subscapular region.

Results:

Elastofibroma dorsi was incidentally confirmed via CT scan in 36 of the 4,435 patients, including 8 males and 28 females, with a mean age of 76.6 years, yielding a prevalence of 0.8%. Elastofibroma dorsi was more common in females, with a 3.3-fold higher prevalence (77.8%) as compared to males (22.2%); however, this difference was not statistically significant (p>0.05). Twenty-five (69.44%) patients had unilateral EFD and 11 (30.56%) had bilateral EFD. Right-sided EFD was encountered in 60% of females and 50% of males. Furthermore, there was no statistically significant correlation between the size of EFD and the patient’s gender or age (p>0.05).

Conclusion:

Elastofibroma dorsi is a rare but uncommon incidental finding on routine chest CT examination encountered in 0.8% of elderly Saudi patients.

Extra-Abdominal Desmoid-Type Fibromatosis Mimicking Myxofibrosarcoma

A 27-year-old woman was confirmed to have extraabdominal desmoid-type fibromatosis. Desmoid-type fibromatosis is a very rare connective tissue neoplasm with the extraabdominal type even more rare. It is most commonly found in proximal structures such as shoulders, neck, chest, and extremities. There are few case reports for desmoid-type fibromatosis located in paraspinal soft tissue. We report a case of desmoid-type fibromatosis mimicking a myxofibrosarcoma. Teaching Point: Even if there are suggestive findings for malignant soft tissue tumor on radiologic evaluation, histological confirmation is necessary before surgical treatment.

Features of ultrasound and contrast enhanced ultrasound in superficial desmoid-type fibromatosis: A series of 19 cases

This study aimed to describe the characteristics of superficial desmoid fibromatosis (DF) using two-dimensional and contrast-enhanced ultrasonography, intending to improve diagnostic accuracy. We retrospectively analyzed 19 cases of superficial DF confirmed by surgery or core-needle biopsy in our hospital from January 2018 to August 2020. All patients underwent two-dimensional and contrast-enhanced ultrasound (CEUS) examination. Nineteen patients included 15 women and 4 men, with an average age of 33.37±12.13 years old. The mean size of lesions was 4.78±1.99 cm. On ultrasound, all lesions presented as solitary heterogeneous hypoechoic masses; 13 presented with ill-defined margins. Ten lesions (52.63%) presented with fusiform shapes, and 11 lesions (57.89%) presented with the "fascial tail" sign. CEUS suggested the tumors were hyperenhanced, with an enhanced pattern of rapid wash-in and slow wash-out. Four lesions (21.05%) showed an enlarged scope in the CEUS image compared with the grayscale ultrasound image. In conclusion, an ill-defined heterogeneous hyperechoic appearance with fusiform-shaped and "fascial tail" signs on US and heterogeneous hyperenhancement with an enlarged scope on CEUS are valuable clues in the diagnosis and treatment of superficial DF.