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Background. Spindle cell/sclerosing rhabdomyosarcoma is a rare neoplasm and has an aggressive clinical course. Because of its rarity, we performed a multi-institutional collaboration to comprehend the overarching clinical, histopathological, and immunohistochemical characteristics of a cohort of spindle cell/sclerosing rhabdomyosarcoma. Materials and Methods. Forty-five patients with spindle cell/sclerosing rhabdomyosarcoma were identified. Demographics, clinical, histopathological, and immunohistochemistry data were reviewed and recorded. Results. The patients' age ranged from 1 to 85 years with a male to female ratio of 1.2:1. There were 15 children/adolescents and 30 adults. Eighteen (40%) tumors were located in the head and neck region. Twenty-four (53%) tumors displayed a bimorphic cellular arrangement with hypercellular areas having short, long, and sweeping fascicular and herringbone pattern, and hypocellular areas with stromal sclerosis and associated hyalinized and/or chondromyxoid matrix. Histomorphological differentials considered were leiomyosarcoma, malignant peripheral nerve sheath tumor, fibrosarcoma, nodular fasciitis, liposarcoma, synovial sarcoma, sarcomatoid carcinoma, solitary fibrous tumor, dermatofibrosarcoma protuberans, and schwannoma. Six tumors exhibited marked stromal sclerosis. The myogenic nature was confirmed by immunohistochemistry. Positivity for at least one skeletal muscle-associated marker (MyoD1 and/or myogenin) was observed. Conclusion. Spindle cell/sclerosing rhabdomyosarcoma diagnosis can be challenging as a number of malignant spindle cell neoplasm mimic this entity. Thus a correct diagnosis requires immunohistochemical work up with a broad panel of antibodies. In view of rarity of this neoplasm, further studies on a large cohort of patients with clinical follow-up data are needed for a better understanding of this tumor. [ABSTRACT FROM AUTHOR]

We report a rare case of spindle cell rhabdomyosarcoma. Sarcomas generally exhibit an abnormal increased FDG uptake on 18F-FDG PET/CT imaging, while spindle cell rhabdosarcomas exhibits a significantly increased lesion uptake on 68Ga FAPI PET/CT imaging compared to 18F-FDG. This case suggests that 68Ga-FAPI PET/CT has potential value in evaluating spindle cell rhabdomyosarcoma. [ABSTRACT FROM AUTHOR]

Para-testicular rhabdomyosarcoma (PTRMS) is a rare tumor, and it accounts for 7% of all rhabdomyosarcoma tumors. Among all the rhabdomyosarcoma (RMS) types, the spindle cell RMS is extremely rare. The present study describes a case of a para-testicular spindle cell RMS that was treated with a radical inguinal orchiectomy (RIO) and right scrotal resection. A 17-year-old male patient presented with a half-year history of a rapidly growing, painless, right scrotal mass. His CT of the pelvic cavity showed a mixed-density mass in the right scrotum, and the maximum cross-sectional area was approximately 76.5 mm x 64.5 mm. An X-ray of the chest demonstrated no evidence of metastasis, and a local surgical excision was performed subsequently. The histopathological and immunohistochemical examination confirmed the final diagnosis of spindle cell RMS. As a newly diagnosed case, strict and regular follow-up is needed. This article focuses on the importance of prompt recognition, diagnosis, pathological features, and appropriate management of para-testicular spindle cell RMS. [ABSTRACT FROM AUTHOR]

Paratesticular embryonal rhabdomyosarcoma is a rare malignancy developed from a mesenchymal tissue of spermatic cord, testicular components. Spindle cell rhabdomyosarcoma (SCR) is a variant of embryonal rhabdomyosarcoma affecting the paratesticular region of adult patients and is even rarer. Given the limited guidelines available to manage SCR and the rarity of reported cases, our report aims to discuss a new case of this entity in a 66-years old Moroccan patient. Paratesticular SCR is a very rare tumor and requires attention from urologists to consider this entity as differential diagnosis when suspecting malignancies in the urogenital region.

We report a rare case of spindle cell rhabdomyosarcoma (ScRMS) in a 20-year-old male patient who visited the dental clinic at the Dental Hospital, Qassim University, with an intraoral swelling on the anterior right side of the maxilla, with a subsequent increase in size with tenderness. Clinical, imaging, and histopathological evaluations involving immunohistochemical staining revealed the diagnosis of ScRMS. This report signifies the importance of detailed examination and interdisciplinary collaboration in diagnosing and managing rare tumors.

Spindle cell rhabdomyosarcoma (SCRM), a rare and distinct subtype of RM, predominantly affects children. While SCRM can manifest in the head and neck regions of adults, primary occurrences in the thorax are exceedingly uncommon. In the present study, a 24-year-old female patient was admitted to the Affiliated Hospital of Zunyi Medical University (Zunyi, China) with a 10-month history of dull pain in the right side of the chest. The patient had previously received treatment for right-sided tuberculous pleurisy at another hospital for 6 months, but the symptoms persisted, and the chest pain progressively worsened. A chest computed tomography scan now revealed a large mass in the right thorax. Pathological examination following surgical resection confirmed a diagnosis of SCRM. The patient did not undergo standardized postoperative chemoradiotherapy and the 5-year follow-up examination indicated tumor recurrence. Primary thoracic SCRM is a rare tumor that morphologically resembles other spindle cell tumors. Immunohistochemistry is crucial for an accurate diagnosis, and surgical resection remains the primary treatment approach. The clinicopathological features, molecular genetic characteristics and biological behavior of SCRM are largely unknown due to its rarity. Consequently, large-sample studies are essential to enhance the understanding of this tumor and advance precision medicine treatments. [ABSTRACT FROM AUTHOR]

Background: Rhabdomyosarcoma (RMS) is the most common soft tissue tumor in children, and its most common pathological types include embryonal RMS and alveolar RMS. In contrast, spindle cell RMS (SRMS) is a rare type. Moreover, the tongue is a rare primary site of RMS, and infancy is a rare age at onset. Case presentation: Two infants were diagnosed with lingual RMS at 3 and 5 months after birth, respectively, and were admitted to Beijing Children's Hospital. The pathological type in both cases was SRMS. Both were classified as low-risk and were treated with surgery and chemotherapy. Case 1 was in complete remission at the latest follow-up, and Case 2 had a relapse 10 months after stopping chemotherapy, achieving complete remission after the multimodal treatment of chemotherapy, surgery, and radiotherapy. The venous blood gene test of the two infants did not indicate a pathogenic mutation or a possible pathogenic mutation related to RMS. In Case 1, variants of the CDK4 and BRCA1 genes, both with unknown significance and a possible relation to RMS, were detected. In Case 2, three gene variants of unknown significance that were possibly associated with RMS--TRIP13, APC, and RAD54L--were identified. Conclusion: Lingual RMS in infants is rare. Its clinical manifestations lack specificity, and early recognition is complex. The success and timing of local treatment are important prognostic factors. Genetic testing may be helpful for the early detection of tumor susceptibility and the estimation of prognosis. [ABSTRACT FROM AUTHOR]

We report a rare case of spindle cell rhabdomyosarcoma. Sarcomas generally exhibit an abnormal increased FDG uptake on 18F-FDG PET/CT imaging, while spindle cell rhabdosarcomas exhibits a significantly increased lesion uptake on 68Ga FAPI PET/CT imaging compared to 18F-FDG. This case suggests that 68Ga-FAPI PET/CT has potential value in evaluating spindle cell rhabdomyosarcoma.

Spindle cell rhabdomyosarcoma (RMS) is a rare variant of RMS accounting for up to 10% of cases in infants. In older children and adults, spindle cell RMS is associated with MYOD1 mutations and a poor prognosis. In infants, it is associated with recurring fusions involving NCOA2 and VGLL2. Reports in the literature suggest a favorable prognosis for this subset, however, little is known about treatment and outcome data of infants with spindle cell RMS. Characteristics, treatment, and outcome of an international cohort of 40 patients aged ≤ 12 months with spindle cell RMS treated from 1997 to 2018 were evaluated. Localized disease (LD) was diagnosed in 39 patients. The median age at diagnosis was 2.5 months (range 0–12 months). Expert pathologic review confirmed the diagnosis of spindle cell RMS in all patients. Among 26 tumors that had molecular evaluation, 13 had rearrangements of NCOA and/or VGLL. Multimodal treatment of infants with LD included conventional (age adjusted) chemotherapy (n = 37), resection (n = 31) and radiotherapy (RT) (n = 5, brachytherapy in 3). Complete remission was achieved in 37/39 patients. Progressive disease occurred in two infants, relapsed disease in three. Microscopically complete surgical resection was associated with five-year event-free survival (EFS) and overall survival (OS) of 100%. Two patients with tumors ≤ 5 cm were treated with microscopically complete resection only and were alive 1 and 4.2 years after diagnosis. The 5-year EFS and OS for infants with LD were 86% (±11; CI 95%) and 91% (±9; CI 95%), respectively. One patient had metastatic disease (NCOA fusion positive) with primary tumor in head and neck and brain metastases. This patient died despite chemotherapy and delayed resection of the primary tumor due to respiratory failure secondary to cytomegalovirus infection 1.2 years after diagnosis. Infants with spindle cell RMS have an excellent prognosis. Multimodal treatment including microscopically complete resection of the tumor is strongly recommended. • International cohort of 40 patients aged ≤12 months with spindle cell rhabdomyosarcoma. • Characteristics, treatment, and outcome analyzed in 39 patients with localized disease. • Among 26 tumors that had molecular evaluation, 13 had rearrangements of NCOA2 and/or VGLL2. • The 5-year EFS and OS for infants with localized disease were 86% and 91%, respectively. [ABSTRACT FROM AUTHOR]

Abstract Background Rhabdomyosarcoma (RMS) in infants is a particular entity with various clinical presentations and outcomes. To better understand the clinical heterogeneity of RMS in infants, an integrative clinical, histological, and molecular analysis was performed. Methods From 1989 to 2015, 37 infants aged less than 6 months with a diagnosis of RMS and archival tumor materials were identified in France. Clinical data, central pathologic review, and molecular profile including RNA sequencing were analyzed. Results Nineteen patients (51%) had embryonal RMS (ERMS) (including three highly differentiated ERMS with PTCH deletion), eight (22%) had spindle cell RMS (SRMS) (three VGLL2‐, one NTRK‐, and two (B)RAF‐fusions), six (16%) had alveolar RMS (ARMS) (all FOXO1‐ or PAX3‐fusion), two had unclassified RMS, and two poorly differentiated RMS were retrospectively diagnosed as rhabdoid tumors (RT) with loss of INI1 expression. The two RT patients died of rapid disease progression. Five‐year event‐free (EFS) and overall survival (OS) for RMS were 62% (95%CI, 47‐82) and 52% (95%CI, 37‐72). Eleven patients (31%) relapsed and four (11%) had primary refractory disease (all ERMS). In univariate analysis, EFS and OS were only associated with histology subtype, with 100% survival of known fusion‐positive SRMS. RNA cluster expression showed three main clusters: ARMS, ERMS, and “VGLL2‐fusion” cluster, consisting of SRMS and ERMS. Conclusions Biopathology findings from this study support the different prognosis of infantile RMS. New fusion‐positive SRMS has a very good outcome which may allow more conservative treatment in the future.

Rhabdomyosarcoma (RMS) is a malignant soft tissue neoplasm with its origin in the skeletal muscle and is extremely rare in adults. By the World Health Organization (WHO), a new variant of RMS has been classified, i.e. the spindle cell (Sc) and sclerosing (S) RMS. While the Sc-RMS shows intersecting fascicles of nonpleomorphic spindle cells, the S-RMS is characterized by a marked hyalinization in a pseudovascular growth pattern associated with round-to-spindled tumour cells. According to the analysed data, the Sc/S-RMS variant has a worse outcome than other variants. The new classification of the Sc/S-RMS variant is valuable to the clinical practice. There are not many oral Sc/S-RMS cases reported. The aim of this paper is to demonstrate that an early diagnosis, an adequate treatment and a multidisciplinary approach have a positive effect on the prognosis of the patient. In this study, we analyse a new case of Sc-RMS variant in a young adult with an early diagnosis and a favourable outcome as a result of an appropriated multidisciplinary treatment: early surgery, radiotherapy and chemotherapy treatment. [ABSTRACT FROM AUTHOR]

Dedifferentiated liposarcoma (DDLS) is characterized by a wide histopathological spectrum. Spindle cell type of rhabdomyoblastic dedifferentiation has been rarely described in case of DDLS. A 39-year-old male presented with a recurrent retroperitoneal tumor mass, diagnosed as well-differentiated liposarcoma, for which he underwent surgical excisions on two occasions, followed by adjuvant radiation therapy previously. Computed tomogram scan his of abdomen revealed a large-sized, fat-containing recurrent, retroperitoneal mass, measuring 18.1 cm in the largest dimension. Histopathologic examination of the resected tumor revealed distinct areas of well- and dedifferentiated liposarcoma, including areas reminiscent of a myxofibrosarcoma, further progressing into a high-grade spindle cell sarcoma with fascicular and “Herringbone-like” growth patterns (fibrosarcoma-like). Immunohistochemically, high-grade spindle cell sarcomatous (dedifferentiated) component displayed distinct positivity for desmin and MyoD1, along with focal tumor nuclei, showing nuclear positivity for myogenin. Both well-differentiated liposarcomatous and dedifferentiated components displayed diffuse, intense nuclear positivity for MDM2 (overexpression) and p16INK4A. Furthermore, upon testing tumor sections displaying spindly sarcomatous areas for MDM2 amplification, by FISH technique, nearly all tumor cells displayed MDM2 gene amplification. This case constitutes one of the rare cases of DDLS displaying spindle cell rhabdomyoblastic dedifferentiation. Its diagnostic and treatment implications are discussed herewith.

Background Primary breast sarcoma (PBS) is rare, comprising approximately 1% of breast malignancies. Rhabdomyosarcoma (RMS) accounts for an extremely small proportion of PBSs, often leading to delayed histologic confirmation. Methods Upon reviewing Asan Medical Center’s pathology database between 2000 and 2018, 41 PBS cases were retrieved, including three cases of primary RMS of the breast. Their clinicopathological features were analyzed, and the literature related to PBS and primary RMS of the breast was reviewed. Results We identified three primary breast RMS cases from our institution database, comprising 7.3% of PBS: one case each of spindle cell/sclerosing RMS (ssRMS), alveolar RMS (aRMS), and embryonal RMS (eRMS). All cases involved adolescents or young adults (14, 16, and 25 years, respectively) who underwent mastectomy or radiotherapy and were confirmed using immunohistochemical testing for myogenin, desmin, and myogenic differentiation. The ssRMS patient experienced recurrence at the operation site 4 months post-surgery despite undergoing concurrent chemoradiotherapy. The aRMS patient had multiple metastases at diagnosis and showed FAX3-FOXO1 fusion transcripts; she died 22 months after the diagnosis. The eRMS patient had enlarged axillary lymph nodes; post-radiotherapy, the lesion recurred as multiple metastases to the bone and lung. She died 18 months post-diagnosis. Conclusions Our experience on RMS cases suggests that spindle cell or small round cell malignancy in breasts of young female should raise suspicion for the possibility of primary or secondary RMS. To our knowledge, this is the second report of primary breast ssRMS and it may help clinicians who encounter this rare disease in the future.

Background: Rhabdomyosarcoma (RMS) in infants is a particular entity with various clinical presentations and outcomes. To better understand the clinical heterogeneity of RMS in infants, an integrative clinical, histological, and molecular analysis was performed. Methods: From 1989 to 2015, 37 infants aged less than 6 months with a diagnosis of RMS and archival tumor materials were identified in France. Clinical data, central pathologic review, and molecular profile including RNA sequencing were analyzed. Results: Nineteen patients (51%) had embryonal RMS (ERMS) (including three highly differentiated ERMS with PTCH deletion), eight (22%) had spindle cell RMS (SRMS) (three VGLL2‐, one NTRK‐, and two (B)RAF‐fusions), six (16%) had alveolar RMS (ARMS) (all FOXO1‐ or PAX3‐fusion), two had unclassified RMS, and two poorly differentiated RMS were retrospectively diagnosed as rhabdoid tumors (RT) with loss of INI1 expression. The two RT patients died of rapid disease progression. Five‐year event‐free (EFS) and overall survival (OS) for RMS were 62% (95%CI, 47‐82) and 52% (95%CI, 37‐72). Eleven patients (31%) relapsed and four (11%) had primary refractory disease (all ERMS). In univariate analysis, EFS and OS were only associated with histology subtype, with 100% survival of known fusion‐positive SRMS. RNA cluster expression showed three main clusters: ARMS, ERMS, and "VGLL2‐fusion" cluster, consisting of SRMS and ERMS. Conclusions: Biopathology findings from this study support the different prognosis of infantile RMS. New fusion‐positive SRMS has a very good outcome which may allow more conservative treatment in the future. [ABSTRACT FROM AUTHOR]

Background and objective Rhabdomyosarcoma (RMS) is a rare and malignant mesenchymal tumor characterized by skeletal muscle differentiation. While it is a common soft tissue sarcoma in children, its incidence significantly decreases with advancing age, rendering it exceptionally rare in individuals aged more than 45 years. This study aimed to shed light on the clinicopathological diversity and subtypes of RMS, thereby providing a comprehensive overview for enabling diagnostic precision and therapeutic strategies in treating this infrequently encountered malignancy in adults. Methodology This was a hospital-based cross-sectional study conducted in the Department of Pathology. Patients who were diagnosed with RMS over a period of three years were included in the study. The demographic features such as age and sex and aspects related to the tumor site, size, subtypes of RMS, and immunohistochemical expression were studied. Results A total of 14 cases were included in our study. The age at diagnosis ranged from four months to 65 years with a male-to-female ratio of 1:2.5. The sites of presentation were head and neck, trunk, pelvis, genitourinary tract, and retroperitoneum. The histological types were embryonal, alveolar, pleomorphic, and mixed and spindle cell types. The tumor cells were positive for immunohistochemistry markers desmin, MyoD1, and vimentin. Conclusion This study delved into the clinicopathological intricacies of RMS, offering comprehensive insights into its diverse subtypes. Our findings underscore the unique presentation of RMS in adults, with trunk and genitourinary tracts emerging as primary sites and alveolar and pleomorphic RMS observed as the predominant histological subtypes. Furthermore, the study sheds light on rare subtypes with distinct anatomical distributions., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Mandava et al.)

Sclerosing rhabdomyosarcoma (RMS) is a rare subtype of RMS with unique prominent stromal hyalinization and a pseudovascular architecture. It overlaps morphologically with spindle cell RMS and poses both diagnostic and therapeutic challenges because of its rarity and aggressive clinical course. In this article, we report a case of sclerosing RMS arising from a prior craniotomy site, which demonstrated both sclerosing and spindle cell components. A literature review of RMS with sclerosing morphology identified 122 cases. Our review documents the following: sclerosing RMS occurs in both childhood and adult populations, has a predilection for the head and neck areas, and has a worse prognosis in adults. Sclerosing RMS harbors a high frequency of MYOD1 mutations, conferring a poor clinical outcome. Sclerosing RMS and spindle RMS likely represent a morphologic spectrum of one entity. [ABSTRACT FROM AUTHOR]

A 25‐year‐old male patient presented with swelling and pain in the mandibular anterior region for the previous 6 months. He had a history of repeated traumatic episodes associated with his lower incisors. A periapical radiograph revealed a radiolucent lesion involving the apices of the lower incisors, whereas cone beam computed tomography revealed a large osteolytic lesion involving all mandibular incisors and loss of labial and lingual cortical plates. Histological, immunohistochemical and bone scan examination of the curetted tissue established a differential diagnosis of spindle cell rhabdomyosarcoma of the anterior mandible. Such rare but life‐threatening oral cancers can be correctly diagnosed and treated only through systematic analysis of clinical findings and examining the diseased tissue with histological and other diagnostic procedures. [ABSTRACT FROM AUTHOR]

Fibroblastic and myofibroblastic tumors comprise a morphologically diverse and biologically variable group of neoplasms that affect a wide age range. Specific entities tend to occur most frequently in infants and young children. Recent years have witnessed a proliferation of information concerning the unique biology of these tumors. In this report, I will review recent findings that serve to further characterize this group of neoplasms. Included will be newer information on fibrous hamartoma of infancy, infantile myofibromatosis, lipofibromatosis, and infantile fibrosarcoma and tumors resembling it, including primitive myxoid mesenchymal tumor of infancy and new genetic entities. I will also discuss the differential diagnosis, which includes spindle cell rhabdomyosarcoma, dermatofibrosarcoma protuberans, and calcifying aponeurotic fibroma.

Background: Based on their distinctive histologic and genetic features, the latest WHO classification of soft tissue tumors includes four pathologic variants of rhabdomyosarcoma (RMS): embryonal (ERMS), alveolar (ARMS), spindle cell-sclerosing (SRMS-ScRMS) and pleomorphic RMS. The aim of this study focused on a detailed clinicopathologic and survival analysis of head and neck RMS (HNRMS) using the latest pathologic and molecular criteria reflecting this new subclassification in a large cohort.Patients and Methods: Patients managed for HNRMS in our institution (1996-2015) were analyzed. The presence of a FOXO1 fusion was required for the classification of ARMS. MYOD1 mutations in SRMS-ScRMS were tested when material available. Univariate and multivariate analyses were performed to evaluate variables related to overall survival (OS).Results: Ninety-nine HNRMS patients (52 males and 47 females, mean of 16years) were included in the study after pathologic re-review. The most common location was parameningeal (PM) (n=64), followed by non-orbital/non-PM (n=25) and orbital (n=10). There were 53 ERMS, 33 fusion-positive ARMS and 13 SRMS-ScRMS [SRMS (8); ScRMS (5)]. The 5-year OS rate for ERMS patients was significantly higher (82%) compared to ARMS (53%) and SRMS-ScRMS (50%) [SRMS (75%); ScRMS (30%)]. Univariate analysis showed that survival was dependent on histology (P=0.012), tumor size >5cm (P<0.001), regional lymph node involvement (P=0.002), metastasis at initial presentation (P<0.001), stage (P<0.001), and recurrence (P=0.002). Multivariate analysis confirmed histologic subtype to be significant (P=0.043).Conclusion: Our findings reinforce that HNRMS is a heterogenous disease with ARMS and SRMS-ScRMS having an equally unfavorable outcome. [ABSTRACT FROM AUTHOR]

This systematic review aimed to analyze the clinicopathological profile and relevant prognostic factors of head and neck rhabdomyosarcoma in pediatric patients. The search was carried out in the electronic search portals PubMed, Lilacs, Embase, Scopus, and Web of Science. The search yielded studies that were then analyzed regarding study topic, data extraction, and risk of bias using the STROBE (Strengthening the Reporting of Observational Studies) guidelines. Finally, three studies were included for qualitative analysis. Most of the cases involved embryonic and alveolar rhabdomyosarcoma. Expression of MYOD1 was highly correlated with diagnosis of spindle cell/sclerosing rhabdomyosarcoma, which appears to have a poor prognosis in children. Furthermore, tumor size <5 cm and absence of metastasis accompanied by complete resection and administration of adjuvant therapies such as chemotherapy and radiotherapy favored a better prognosis.

Recently, spindle cell/sclerosing rhabdomyosarcoma ( RMS) has been recognized as another distinct variant of a RMS. We evaluated clinicopathological features of 21 cases of spindle cell and sclerosing RMS and performed fluorescent in situ hybridization ( FISH) testing in 10 (47.6%) tumours. Twenty-one tumours occurred in 16 males and 5 females (mean age, 19.7 years); commonly in the head and neck region (8) (38%) and extremities (7) (33.3%), followed by paratesticular region (2) (9.5%), chest wall (1), abdomen (1), pelvis (1) and paraspinal region (1). Average tumour size was 7.9 cm. Histopathologically, tumours that were spindle cell type (8) (38%) mostly occurred in the head and neck region, while sclerosing type (10) (47.6%) mostly occurred in the extremities. Remaining three (14.2%) tumours were mixed (sclerosing with spindle cell type). Tumour areas resembling embryonal RMS ( ERMS) and alveolar RMS ( ARMS) were noted in eight and three tumours respectively. Immunohistochemically, tumour cells were positive for desmin (21/21) (100%), MyoD1 (19/19) (100%), myogenin (13/15) (86.6%), SMA (2/3) and MIC2 (1/8) (12.5%). On FISH testing, none of the 10 tumours exhibited RMS1 ( PAX3- FOXO1) or RMS 2 ( PAX7- FOXO1) fusion. Eighteen patients underwent surgical resection and were offered adjuvant chemotherapy ( CT) (4 cases), adjuvant CT + radiotherapy ( RT) (4 cases) and adjuvant RT (1 case). Two patients underwent CT and a single patient received CT + RT. On follow-up (16 cases) (2-36 months), six tumours recurred and nine metastasized. Spindle/sclerosing RMSs are aggressive tumours and occur commonly in the head and neck and extremity sites. These tumours are histopathologically interrelated. Their immunohistochemical and cytogenetic profile is closer to ERMS than ARMS. [ABSTRACT FROM AUTHOR]

Background: Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood, while in adults it is one of the rarer tumors. Its prognosis is better in children with current treatment modalities; however, it carries poorer prognosis in adults. Recent data on adult RMS is scarce from our part of world. We report outcomes of adult patients with RMS, and with 40 patients; it is the first study to publish such a large data from Pakistan., Methods: This was a retrospective study that included 64 adult patients aged 18 years and older. After data extraction and scrutiny, a total of 40 patients were segregated with diagnosis of RMS of various varieties who were treated and followed up subsequently. International Business Machines (IBM) Statistical Package for Social Sciences (SPSS), version 26 (IBM Corp., Armonk, NY) was used to evaluate all of the gathered data., Results: Embryonal RMS (ERMS) was the most common subtype. Factors favoring better overall survival (OS) at 5 years were absence of nodal and distal metastases, treatment with surgery, margin negative resection, and absence of residual disease on postoperative imaging. Adjuvant radiation therapy (XRT) for positive resection margins as well as for residual disease on postoperative imaging also favored better OS at 5 years. Chemotherapy did impart a trend towards better OS; however, it was not significant. Histopathologic subtype and tumor size did not have any significant impact on outcomes. Median progression free survival (PFS) was 11 months and median OS was 15 months., Conclusions: Adult RMS is a rare disease entity with widely heterogeneous clinical picture and poorer outcomes as compared to the disease of childhood and adolescence. Further prospective studies with larger sample size are required to establish role of patient, disease, and treatment-related factors affecting outcomes in our population., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2022, Rab et al.)

The mammalian Vestigial-like (VGLL) transcriptional cofactor family of proteins VGLL1-4 has recently emerged as an important player in the tumorigenesis of diverse neoplasms. The role of VGLL3 in soft tissue tumors is exemplified by its amplification in myxoinflammatory fibroblastic sarcoma and its rearrangement (fused to CHD7, CHD9, or MAMLD1) in hybrid schwannoma-perineurioma. This study characterizes a distinctive low-grade myogenic neoplasm with a striking predilection for the head and neck, characterized by VGLL3 fusions. The study includes five males and one female patient, aged 30-71 years (median, 56). Three tumors originated in the tongue, with one case each in the nasopharynx, oral cavity, and oropharynx. The VGLL3 fusion partners included TCF12 (n = 3), EP300 (n = 2), and PPARGC1A (n = 1). The tumor size range was 0.8-1.6 cm (all, but one, was <1 cm). Histologically, all tumors displayed bland spindle to ovoid cells arranged into vague fascicular and diffuse patterns. Mitotic activity ranged from 1 to 7 per 10 HPFs. Five tumors were muscle-centered and infiltrative, and one was centered beneath nasopharyngeal mucosa. Immunohistochemistry revealed consistent expression of desmin (diffuse in four and patchy in two cases) associated with patchy smooth muscle actin expression (4/6), and focal reactivity for myogenin (5/6) and myoD1 (1/3). All patients were managed surgically; one patient each received adjuvant radio- or chemotherapy. Three patients with follow-up were without disease at 8, 19, and 60 months and one was alive with unknown disease status at 24 months. All VGLL3 fusions were in-frame and involved exon 2, fused with either TCF12 exon 16, EP300 exon 31, or PPARGC1A exon 5, respectively. This series characterizes a distinctive subset of spindle cell rhabdomyosarcoma (RMS) with a predilection for the head and neck in adults, defined by VGLL3 fusions, likely indolent behavior and limited rhabdomyoblastic differentiation. Further delineation of this entity and differentiation from more aggressive molecular subtypes of spindle cell RMS is mandatory to define the most appropriate therapeutic strategy and avoid overtreatment., (© 2022 The Authors. Genes, Chromosomes and Cancer published by Wiley Periodicals LLC.)

Infantile rhabdomyofibrosarcoma is a rare form of soft-tissue tumor often associated with difficulties in diagnosis. The disease is positioned intermediately between rhabdomyosarcoma and infantile fibrosarcoma in terms of clinical presentation, immunohistochemistry, behavior, morphology and ultrastructural features. Reports of rhabdomyofibrosarcoma cases are limited in the literature. The present case describes a 26-month-old female who presented with a slowly progressive, soft-tissue mass in the right chest wall. The mass was successfully treated with surgery. Using histopathology, the tumor was diagnosed and classified as infantile rhabdomyofibrosarcoma. The patient has been followed-up for 2 years and is currently in good condition. The present case demonstrates that early, radical, local surgery and multidisciplinary cooperation were successful for the treatment of rhabdomyofibrosarcoma, and close follow-up highly recommended. [ABSTRACT FROM AUTHOR]

Abstract: The use of a relatively nontoxic tyrosine kinase receptor inhibitor, imatinib mesylate (IM) (STI-571), has increasingly become a valuable therapeutic alternative in some KIT (CD117)-overexpressing neoplasms potentially because of the presence of KIT-activating mutations. As the treatment eligibility for this drug hinges on CD117 expression, KIT immunostaining has recently been widely examined in various different tumors. We examined CD117 expression in pediatric embryonal rhabdomyosarcomas (RMSs) to identify its eventual prognostic impact and to evaluate its effect on tumorigenesis. This study included two spindle cell (leiomyomatous) variants, two botryoid variants, and 21 conventional embryonal RMSs. Sections from paraffin-embedded tumor samples were immunostained by a standard SABC technique using c-kit polyclonal antibody with antigen retrieval. In all the series, the percentage of CD117 positivity was 12%. Staining was strong in two of two spindle cell variants, in zero of two botryoid variants, and in one of 21 conventional embryonal RMSs. In Spearman''s correlation analysis, there was statistical relationship between the presence of CD117 expression and the histological subtype of RMS. Kaplan–Meier analysis revealed no prognostic significance of CD117 expression for survival. The present study demonstrated a very limited expression of CD117 in pediatric embryonal RMS other than in the spindle cell variant. This finding suggested that the stem cell factor/c-kit pathway may be implicated in the tumorigenesis of spindle cell RMSs. Therefore, the mutation of c-kit gene must be prospectively examined in larger series of RMSs. If it can be verified that tissue expression of CD117 reflects the mutation of c-kit gene, IM can be considered a targeted therapy for CD117-expressing RMSs, particularly the spindle cell variant. [Copyright &y& Elsevier]