Impact of COVID-19 pandemic on bone and soft tissue sarcoma patients' consultation and diagnosis.

The coronavirus disease (COVID-19) pandemic negatively affected the diagnosis and treatment of several cancer types. However, this pandemic's exact impact and extent on bone and soft tissue sarcomas need to be clarified. We aimed to investigate the effect of the COVID-19 pandemic and emergency declaration by the local government on consultation behavior and clinical stage at diagnosis of bone and soft tissue sarcoma. A total of 403 patients diagnosed with bone and soft tissue sarcoma who initially visited three sarcoma treatment hospitals between January 2018 and December 2021 were included. The monthly number of newly diagnosed soft tissue sarcoma patients was reduced by 25%, and the proportion of soft tissue patients with stage IV disease at diagnosis significantly increased by 9% during the COVID-19 pandemic compared to before the COVID-19 pandemic. Furthermore, the monthly number of new primary bone and soft tissue sarcoma patients significantly decreased by 43% during the state of emergency declaration. The COVID-19 pandemic had a negative impact on soft tissue sarcoma patients' consultation behavior and increased the proportion of advanced-stage patients at initial diagnosis. An emergency declaration by the local government also negatively affected primary bone and soft tissue sarcoma patients' consultation behavior.

Atypical Presentation of Tenosynovial Giant Cell Tumor on the Hallucal Flexor Tendon Sheath: A Case Report.

Tenosynovial giant cell tumor (TGCT) is a rare type of neoplasm that may be locally aggressive but is most often benign and can be divided into two subtypes: localized and diffuse. It tends to develop in the joints, bursae, and tendon sheaths primarily in the digits of the hand and less commonly in the forefoot. This soft-tissue mass has many possible differential diagnoses, including lipoma, ganglion cyst, plantar fibroma, and various sarcomas; surgical excision is usually indicated to reach a definitive diagnosis and rule out malignancy. We report a rare case of a 30-year-old woman with atypical plantar hallucal pain and a palpable mass on the plantar lateral aspect of the left hallux. Surgical excision and histopathologic evaluation confirmed a TGCT of the left hallucal flexor tendon sheath. Although it bears clinical resemblance to several other soft-tissue masses, TGCT has numerous pathognomonic features evident with advanced imaging and histologic analysis that help the physician obtain an accurate diagnosis and proceed with appropriate treatment.

[Applications of artificial intelligence for imaging-driven diagnosis and treatment of bone and soft tissue tumors].

Bone and soft tissue tumors occur in the musculoskeletal system, and malignant bone tumors of bone and soft tissue account for 0.2% of all human malignant tumors, and if not diagnosed and treated in a timely manner, patients may be at risk of a poor prognosis. Image interpretation plays an increasingly important role in the diagnosis of bone and soft tissue tumors. Artificial intelligence (AI) can be applied in clinical treatment to integrate large amounts of multidimensional data, derive models, predict outcomes, and improve treatment decisions. Among these methods, deep learning is a widely employed technique in AI that predominantly utilizes convolutional neural networks (CNN). The network is implemented through repeated training of datasets and iterative parameter adjustments. Deep learning-based AI models have successfully been applied to various aspects of bone and soft tissue tumors, encompassing but not limiting in image segmentation, tumor detection, classification, grading and staging, chemotherapy effect evaluation, recurrence and prognosis prediction. This paper provides a comprehensive review of the principles and current state of AI in the medical image diagnosis and treatment of bone and soft tissue tumors. Additionally, it explores the present challenges and future prospects in this field.

Intramuscular cysticercosis of the forearm mimicking a soft tissue tumour.

A man in his 20s presented with a painless, slow-growing firm swelling in the anterolateral aspect of his left forearm. The swelling had been present for 1 year and measured 10×12 cm. Clinically, a differential diagnosis of soft tissue sarcoma, lipoma, neurofibroma, dermoid cyst and hydatid cyst of the extremity was considered. MRI suggested a primary intramuscular hydatid cyst. However, fine-needle aspiration was inconclusive, and ELISA for immunoglobulin G antibodies to echinococcal antigen in serum was negative. A wide-local complete surgical excision of the lesion was planned. Intraoperatively, a well-defined, tense cystic swelling with surrounding dense adhesions was found within the intramuscular plane. Histopathological examination of the cyst wall revealed cysticercosis. The patient recovered uneventfully. This case highlights that solitary intramuscular cysticercosis, although rare, should be included in the differential diagnosis of an isolated soft tissue mass, particularly in endemic areas.

Distribution Patterns of Benign and Malignant Bone and Soft Tissue Tumors and Tumor-like lesions in the Hindfoot and Ankle: A 12.5-year Analysis.

BACKGROUND/AIM: Benign and tumor-like lesions of the hindfoot and ankle are common, whereas malignant entities are rare. Accurate evaluation and timely management of these lesions can be challenging, making it crucial to understand their incidence and anatomic localization. This study retrospectively analyzed the distribution of benign and malignant bone and soft tissue tumors in the hindfoot and ankle. PATIENTS AND METHODS: This study included patient data from a single center, such as age, sex, histologic diagnosis, and anatomic location over a 12.5 year period. RESULTS: Of the 105 cases reviewed, 19 cases (18.1%) were osseous lesions and 86 cases (81.9%) were soft tissue lesions. The latter were divided into 77 benign and 9 malignant cases, resulting in an overall malignancy rate of 8.6%. The most common osseous lesion was the intraosseous ganglion (n=12). The majority of benign soft tissue lesions (75.3%) were located in the hindfoot, with TGCT, schwannoma, and ganglion cysts being the most common types. The nine malignant cases were distributed among seven entities and were evenly distributed among both regions and sexes. Malignant cases had a higher mean age (59.2 years) compared to benign cases (40.8 years; p=0.001). CONCLUSION: Tumors, tumor-like lesions, and pseudotumors represent an important aspect of ankle pathology. The majority of focal masses and swellings are benign soft tissue or osseous lesions, but malignant entities can occur and may be mistaken for benign conditions. Preoperative imaging and histopathologic examination are essential, and preoperative presentation to a multidisciplinary tumor board is recommended in unclear cases.

Importance of encouraging early presentation and referral for soft tissue lesions.

Delays in both the presentation and referral of soft tissue lesions have been extensively recorded in the existing literature. Such delays may result in lesions invading into surrounding tissues including neurovascular structures, increasing the risk of surgical complications and adverse consequences for patients. Delays in initiation of treatment of soft tissue sarcomas have further been associated with increased rates of metastasis. As such, patients' recovery may be limited due to late presentations, and residual morbidity may be more pronounced. This case report presents the predicament of a fungating mass in a female in her 80s in order to emphasise the importance of identifying and referring to such lesions early on. The referral delay of this lesion highlights the impact increasing awareness of this condition among both healthcare professionals and patients could have by allowing for earlier interventions.

Soft Tissue Fine-Needle Aspiration: Current and Future Impact on Patient Care.

Soft tissue neoplasms pose many diagnostic challenges on fine-needle aspiration (FNA), owing largely to their rarity, large number of entities, and histologic diversity. Advances in ancillary testing now allow detection of the characteristic immunophenotypes and molecular alterations for many neoplasms and include reliable surrogate immunohistochemical markers for underlying molecular events that are highly efficient in small biopsies. A morphology-based framework is recommended to guide appropriate differentials and judicious selection of ancillary tests for small biopsies. The accurate diagnosis of soft tissue tumors is crucial for patient management and prognostication, with many potential implications in this era of precision medicine.

Understanding multicentric haemangioendothelioma: diagnostic dilemmas and treatment strategies.

Epithelioid haemangioendothelioma (EH) is a rare malignant vascular tumour occurring mainly in the liver and lungs, with bones being a rare site and primarily seen in the adult population. This case presents a male patient in his 40s who presented to the outpatient department with a chief issue of a painless swelling over the inguinal region for 4 months, gradually increasing in size, along with a history of a gradually enlarging, painless mass on his left knee over the past 5 years. Despite occasional discomfort during physical activities, the mass exhibited no associated trauma, fever, weight loss or systemic symptoms. Physical examination revealed a firm mass on the left knee and a matted lymph nodal swelling in the left inguinal region. Subsequent imaging studies identified multiple soft tissue lesions, osseous involvement and pulmonary metastases, suggestive of multicentric haemangioendothelioma. The patient underwent surgical excision of the inguinal mass and fixation of a pathological fracture in the left femur. He is currently undergoing chemotherapy and is scheduled for regular follow-up appointments. This case underscores the importance of thorough diagnostic evaluation and multidisciplinary management in complex oncological conditions like multicentric haemangioendothelioma.

EMA-Positive Superficial ALK-Rearranged Myxoid Spindle Cell Neoplasm Masquerading as Perineurioma/Hybrid Nerve Sheath Tumor.

ABSTRACT: Superficial anaplastic lymphoma kinase (ALK)-rearranged myxoid spindle cell neoplasm (SAMS) is a recently described entity which coexpresses ALK, CD34, and commonly S100. These neoplasms are characterized morphologically by concentric spindle cell whorls and cords and are commonly set in an abundant myxoid to myxocollagenous stroma, thus mimicking perineurioma or hybrid nerve sheath tumor. EMA immunostain has been reported to be negative in SAMS which helps in excluding the latter entities. Herein, we report the first EMA-positive SAMS of the right leg in a 37-year-old female patient masquerading as perineurioma/hybrid nerve sheath tumor. The tumor morphologically was comprised of spindle cells arranged in loose whorls and short fascicles set in myxoid to collagenous stroma and coexpressed CD34 and EMA, reminiscent of perineurioma. S100 showed focal staining. ALK immunostain was subsequently performed and was positive. ALK gene rearrangement was identified by fluorescence in situ hybridization break-apart assay and was further confirmed by next-generation sequencing-based RNA sequencing demonstrating FLNA::ALK fusion, thus supporting the diagnosis of SAMS. In conclusion, EMA can be expressed in SAMS, thus posing as a diagnostic pitfall. ALK immunostain and molecular studies are essential for confirming the diagnosis of SAMS and excluding potential mimickers, particularly perineurioma or hybrid nerve sheath tumor.

ISLET-1 expression in soft tissue neoplasms reveals high sensitivity but moderate specificity for desmoplastic small round cell tumors and potential utility as a diagnostic biomarker.

ISLET-1 (ISL1) is a LIM-homeodomain transcription factor. Selective ISL1 expression is shown in neuroendocrine, non-neuroendocrine, and some soft tissue tumors including desmoplastic small round cell tumor (DSRCT). We assessed the specificity of ISL1 (clone EP283, 1:500, Cell Marque) in 288 soft tissue tumors, which included 17 DSRCTs and other histologic mimics. Positive staining threshold for ISL1 was set to >10 % of neoplastic cell nuclei at moderate intensity. ISL1 IHC was positive in 15/16 (94 %) DSRCTs with 75 % showing diffuse (>50 %) expression. ISL1 was positive in 1/10 (10 %) Ewing sarcomas (EWS), 7/13 (54 %) alveolar rhabdomyosarcoma (RMS), 14/22 (63 %) embryonal RMS, 7/14 (50 %) synovial sarcomas, 15/16 (93 %) neuroblastoma, 1/5 (20 %) Wilms tumor, 2/4 (50 %) olfactory neuroblastoma, and all 9 Merkel cell carcinomas. Other tumors, including all CIC::DUX4 sarcomas, were negative except 3/27 leiomyosarcomas, and 1 each of angiosarcoma, myxoid liposarcomas, inflammatory myofibroblastic tumor, malignant peripheral nerve sheath tumor, tenosynovial giant cell tumor, dedifferentiated LPS, and 1 ectomesenchymoma. In summary, among the soft tissue tumors tested, ISL1 is a highly sensitive but moderately specific marker for DSRCT and may be useful to distinguish from round cell mimics including EWS and CIC::DUX4 sarcomas. The oncogenic role of ISL1 in these tumors warrants further investigation.

Extraskeletal Ewing Sarcoma Disguised as a Vascular Malformation.

Extraskeletal Ewing sarcoma (EES) is a rare entity, accounting for only 3% of lesions encountered in upper extremity. We present two paediatric patients, who were initially diagnosed with a vascular malformation based on clinical assessment and imaging. Final histopathology revealed Ewing sarcoma of soft tissue origin, confirmed by immunohistochemical analysis. Hand surgeons, who are routinely approached for a myriad of hand pathologies, should be wary and consider EES as a differential when treating such lesions. A multidisciplinary approach with an appropriate treatment algorithm can help in a speedy diagnosis, improving the long-term prognosis of the disease. Level of Evidence: Level V (Therapeutic).

MUC5AC immunoreactivity in scattered tumor cells is useful for diagnosing CIC-rearranged sarcoma.

CIC-rearranged sarcoma is an aggressive round cell sarcoma, and an alternative ATXN1/ATXN1L fusion has been reported. Diagnosis may be difficult, and molecular assays may suffer from imperfect sensitivity. Characteristic histology and ETV4 immunohistochemical positivity are diagnostically helpful. However, ETV4 staining is unavailable in most laboratories. Here, we explored the diagnostic utility of MUC5AC immunohistochemistry in CIC-rearranged sarcomas. All 30 cases, except one, of CIC-rearranged sarcomas and 2 ATXN1-rearranged sarcomas were positive for MUC5AC, although the number of immunopositive cells was generally low (< 5%) in most samples, representing a characteristic scattered pattern. The only MUC5AC-negative case had the lowest tumor volume. Among the 110 mimicking round cell malignancies, 12 tumors showed MUC5AC positivity, including occasional cases of synovial sarcoma and small cell carcinoma, whereas the remaining 98 samples were negative. Despite its lower specificity than that of ETV4 and sparse reactivity that requires careful interpretation, MUC5AC may serve as a useful marker for CIC/ATXN1-rearranged sarcoma because of its wider accessibility.

The prediagnostic general practitioner care of sarcoma patients: A real-world data study.

BACKGROUND: Limited understanding exists regarding early sarcoma symptoms presented during general practitioner (GP) consultations. The study explores GP visit patterns and recorded diagnoses in the 12 months preceding sarcoma diagnosis. METHODS: Sarcoma cases diagnosed from 2010 to 2020 were identified through the Netherlands Cancer Registry alongside general practice data. Sarcoma cases were age and gender matched to cancer-free controls (2:1 or 1:1 ratio). RESULTS: A total of 787 individuals with soft-tissue sarcoma (STS) and 188 individuals with bone sarcoma (BS) were identified. There was a significant difference in monthly GP contacts from 4 months to the last month before STS diagnosis, and 2 months before BS diagnosis between cases and controls. Most prevalent diagnoses recorded by the GP for STS cases included musculoskeletal neoplasm (26.6%), uncomplicated hypertension (15.6%), and cystitis/other urinary infections (12.2%). For BS cases, musculoskeletal neoplasm (42.8%), knee symptoms/complaints (9.7%), and shoulder symptoms/complaints (9.7%) were most frequent. CONCLUSIONS AND DISCUSSION: A significant difference in GP contacts between cases and controls preceding sarcoma diagnosis. STS cases were predominantly diagnosed with nonspecific symptoms, whereas BS cases with diagnoses more suggestive of BS. Better understanding of the prediagnostic trajectory could aid GPs in early identification of sarcoma.

Synovial hemangioma presenting with chronic painful infrapatellar mass: a case report.

BACKGROUND: Synovial hemangiomas are rare benign vascular anomalies surrounded by a synovial lining and were first described by Bouchut in 1856. These neoplasms can develop in the intra-articular region, resulting in effusions and knee pain. However, their cause remains unknown. Prompt diagnosis and intervention are critical to prevent chondral damage. Histopathological examination is used to achieve the diagnosis, which is often delayed because of a lack of specific clinical signs. This report describes a unique case in which a painful infrapatellar mass was diagnosed as a synovial hemangioma. The absence of typical magnetic resonance imaging (MRI) findings highlights the importance of arthroscopic excision for diagnosis and symptom relief. CASE PRESENTATION: A 20-year-old woman presented with persistent anterior left knee pain that became exacerbated when she climbed stairs. Despite previous pain management and physical therapy, she developed a painful lump beneath her patella that worsened over time. She had also undergone arthrocentesis, but this did not relieve her pain. Physical examination revealed a palpable, immobile 5-cm mass along the patellar tendon with limited knee flexion and extension and normal ligament stability. T1-weighted fat-saturated MRI of the left knee with gadolinium-based contrast revealed a lobulated intra-articular mass in Hoffa's fat pad that resembled a soft tissue chondroma. A biopsy of the mass was performed to provide histopathological evidence, confirming the benign nature of the mass. The subsequent excisional arthroscopy, combined with incision enlargement for mass removal, confirmed the histopathologic diagnosis of synovial hemangioma based on the presence of numerous dilated blood vessels and venous proliferation within sections of the synovium. Recovery was complete, and no residual tumor was detected on follow-up MRI after 1 year. CONCLUSION: This case study emphasizes the importance of arthroscopic excision over open surgery for patients with synovial hemangioma. The minimally invasive nature of arthroscopy combined with the well-encapsulated nature and location of the mass facilitates complete resection.

Fluorescence in situ hybridization-negative intra-articular myxoid liposarcoma with complex rearrangements involving EWSR1::DDIT3 detected using nanopore sequencing.

Myxoid liposarcoma (MLPS) is a rare sarcoma, typically arising in deep soft tissues during the fourth to fifth decades of life. Histologically, MLPS is composed of uniform oval cells within a background of myxoid stroma and chicken-wire capillaries. Genetically, MLPS is characterized by the FUS/EWSR1::DDIT3 fusion gene, which generally results from balanced interchromosomal translocation and is detectable via DDIT3 break-apart fluorescence in situ hybridization (FISH). Here, we report an unusual intra-articular MLPS case, negative for DDIT3 break-apart FISH but positive for EWSR1::DDIT3. An 18-year-old female was referred to our hospital complaining of an intra-articular mass in the right knee joint. Histologically, the tumor was mainly composed of mature adipocytes, brown fat-like cells, and lipoblasts. Nanopore sequencing detected DNA rearrangements between EWSR1 and DDIT3 and clustered complex rearrangements involving multiple chromosomes, suggesting chromoplexy. Methylation classification using random forest, t-distributed stochastic neighbor embedding, and unsupervised hierarchical clustering correctly classified the tumor as MLPS. The copy number was almost flat. The TERT promoter C-124T was also detected. This report highlights, for the first time, the potential value of a fast and low-cost nanopore sequencer for diagnosing sarcomas.

Pleomorphic Liposarcoma Unraveled: Investigating Histopathological and Immunohistochemical Markers for Tailored Diagnosis and Therapeutic Innovations.

Liposarcomas are some of the most challenging soft tissue tumors and are subclassified into multiple subtypes with special histologic and molecular features. The peculiarities of each histopathological subtype influence the clinical behavior, management, and treatment of these neoplasms. For instance, well-differentiated liposarcomas are common soft tissue malignancies and usually display a favorable outcome. On the other hand, pleomorphic liposarcoma is the rarest, yet the most aggressive subtype of liposarcoma. This histopathological diagnosis may be challenging due to the scarce available data and because pleomorphic liposarcomas can mimic other pleomorphic sarcomas or other neoplasms of dissimilar differentiation. Nevertheless, the correct diagnosis of pleomorphic liposarcoma is of utmost importance as such patients are prone to develop local recurrences and metastases. Treatment usually consists of surgical excision along with radiotherapy and follow-up of the patients. Therefore, this review aims to assess the complex clinical, histological, and immunohistochemical features of liposarcomas in order to establish how these characteristics influence the management and prognosis of the patients, emphasizing the particularities of pleomorphic liposarcoma.

Fine-needle aspiration cytology of diffuse type tenosynovial giant cell tumor with malignant trasformation and review of literature.

Tenosynovial giant cell tumors (TGCTs) arise from the synovium of joint, bursa, and tendon sheath. Diffuse type often affects large joints, has higher recurrence rates, metastases, and malignant transformation potential compared to the localized type. The cytopathology of TGCT, a fibrohistiocytic neoplasm distinct from other giant cell-rich soft tissue tumors, is rarely reported. Here we describe cytomorphology of a case of TGCT that was initially diagnosed on fine-needle aspiration cytology (FNAC) consisting of a mixture of singly scattered polygonal or spindle mononuclear cells with hemosiderin laden macrophages, inflammatory cells, and a population of multinucleated osteoclast-like giant cells. Persistent symptoms and repeat excision were consistent with high-grade malignant transformation of the TGCT. Atypical cytologic features in a recurrent, infiltrative, or a metastatic lesion should raise suspicion for malignancy.

Pathogenetic and molecular classifications of soft tissue and bone tumors: A 2024 update.

Soft tissue and bone tumors comprise a wide category of neoplasms. Their diversity frequently raises diagnostic challenges, and therapeutic options are continuously developing. The therapeutic success rate and long-term prognosis of patients have improved substantially due to new advances in immunohistochemical and molecular biology techniques. A fundamental contribution to these achievements has been the study of the tumor microenvironment and the reclassification of new entities with the updating of the molecular pathogenesis in the revised 5th edition of the Classification of Soft Tissue Tumors, edited by the World Health Organization. The proposed molecular diagnostic techniques include the well-known in situ hybridization and polymerase chain reaction methods, but new techniques such as copy-number arrays, multiplex probes, single-nucleotide polymorphism, and sequencing are also proposed. This review aims to synthesize the most recent pathogenetic and molecular classifications of soft tissue and bone tumors, considering the major impact of these diagnostic tools, which are becoming indispensable in clinicopathological practice.

It's not always histiocytic sarcoma: Immunocytochemistry to identify two unusual tumors in a Bernese Mountain dog.

A 7-year-old female spayed Bernese Mountain dog was presented for evaluation of hematuria. Incidentally, a right stifle sarcoma was diagnosed via cytology, which raised concern for histiocytic sarcoma (given the patient's signalment) versus another joint-associated sarcoma. Histopathology and immunohistochemistry revealed a CD18-negative, non-histiocytic origin cell population. Findings were consistent with a joint-associated grade II soft tissue sarcoma (STS). The patient's hematuria was progressive over 5 months, and urinary bladder transitional cell carcinoma (TCC) was diagnosed via cystoscopy and histopathology. An enlarged right medial iliac lymph node was identified on routine restaging via abdominal ultrasound 3 months later. Cytology of the lymph node revealed a markedly pleomorphic cell population, again raising concern for histiocytic sarcoma (HS). Other differentials included an anaplastic metastatic population from the joint-associated STS or the TCC. Immunocytochemistry revealed a cytokeratin-positive, CD18-, CD204-, and vimentin-negative cell population, consistent with a carcinoma. DNA was extracted from cytology slides to sequence cells for BRAF mutation status. Sequencing revealed a homozygous V596E (transcript ENSCAFT00845055173.1) BRAF mutation, consistent with the known biology of TCC. In neither case was HS truly present in this patient, but immunocytochemistry provided information that helped to optimize the patient's chemotherapy recommendations.

Proteomic Characterization of Undifferentiated Small Round Cell Sarcomas With EWSR1 and CIC::DUX4 Translocations Reveals Diverging Tumor Biology and Distinct Diagnostic Markers.

Undifferentiated small round cell sarcomas (USRS) of bone and soft tissue are a group of tumors with heterogenic genomic alterations sharing similar morphology. In the present study, we performed a comparative large-scale proteomic analysis of USRS (n = 42) with diverse genomic translocations including classic Ewing sarcomas with EWSR1::FLI1 fusions (n = 24) or EWSR1::ERG fusions (n = 4), sarcomas with an EWSR1 rearrangement (n = 2), CIC::DUX4 fusion (n = 8), as well as tumors classified as USRS with no genetic data available (n = 4). Proteins extracted from formalin-fixed, paraffin-embedded pretherapeutic biopsies were analyzed qualitatively and quantitatively using shotgun mass spectrometry (MS). More than 8000 protein groups could be quantified using data-independent acquisition. Unsupervised hierarchical cluster analysis based on proteomic data allowed stratification of the 42 cases into distinct groups reflecting the different molecular genotypes. Protein signatures that significantly correlated with the respective genomic translocations were identified and used to generate a heatmap of all 42 sarcomas with assignment of cases with unknown molecular genetic data to either the EWSR1- or CIC-rearranged groups. MS-based prediction of sarcoma subtypes was molecularly confirmed in 2 cases where next-generation sequencing was technically feasible. MS also detected proteins routinely used in the immunohistochemical approach for the differential diagnosis of USRS. BCL11B highly expressed in Ewing sarcomas, and BACH2 as well as ETS-1 highly expressed in CIC::DUX4-associated sarcomas, were among proteins identified by the present proteomic study, and were chosen for immunohistochemical confirmation of MS data in our study cohort. Differential expressions of these 3 markers in the 2 genetic groups were further validated in an independent cohort of n = 34 USRS. Finally, our proteomic results point toward diverging signaling pathways in the different USRS subgroups.