Smooth muscle tumors of soft tissue

Incidental deep soft tissue leiomyoma of the groin - a case report and comprehensive review of literature

Leiomyomas are rare, benign tumors arising from smooth muscle cells. Due to the heterogeneous anatomical locations, as well as clinical and radiological findings, early and correct diagnosis is usually tricky. The clinical symptoms depend on the anatomical structure the tumors are compromising by their growth. We present a case of a 53-year-old male patient who suffered from swelling of the right foot and ankle. Initially, arthritis and deep vein thrombosis were ruled out. As the swelling progressed to the entire leg, CT scan was performed showing a tumor compressing the right femoral vein. However, a magnetic resonance imaging (MRI) and a biopsy did not show any conclusive findings. Tumor excision was planned and immunohistochemical staining confirmed leiomyoma. The authors conclude that unspecific, progressive symptoms should prompt further investigation and whenever planning a biopsy, a possible malignant finding should be considered and excision of the biopsy canal together with the tumor must be assured.

Uterine leiomyoma as useful model to unveil morphometric and macromolecular collagen state and impairment in fibrotic diseases: An ex-vivo human study

Collagen is one of the main components of the extracellular matrix (ECM), involved, among all, in the maintenance of the structural support of tissues. In fibrotic diseases, collagen is overexpressed, and its production determines the formation of a significantly stiffer ECM. The cross-linking of high-resolution analytical tools, able to investigate both the tridimensional organization and the secondary structure of collagen in fibrotic diseases, could be useful to identify defined markers correlating the status of this protein with specific pathological conditions. To this purpose, an innovative multidisciplinary approach based on Phase-Contrast MicroComputed Tomography, Transmission Electron Microscopy, and Fourier Transform Infrared Imaging Spectroscopy was exploited on leiomyoma samples and adjacent myometrium to characterize microstructural collagen features. Uterine leiomyoma is a common gynecological disorder affecting women in fertile age. It is characterized by a massive collagen production due to the repairing processes occurring at myometrium level, and, hence, it represents a valuable model to investigate collagen self-organization in a pathological condition. Moreover, to evaluate the sensitivity of this multidisciplinary approach, the effects of eicosapentaenoic (EPA) and docosahexaenoic (DHA) omega-3 fatty acids in collagen reduction were also investigated.

Prognosticators and Prognostic Nomograms for Leiomyosarcoma Patients With Metastasis

Individual survival prediction and risk stratification are of vital importance to optimize the individualized treatment of metastatic leiomyosarcoma (LMS) patients. This study aimed to identify the prognostic factors for metastatic LMS patients and establish prognostic models for overall survival (OS) and cancer-specific survival (CSS). The data of LMS patients with metastasis between 2010 and 2015 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. The entire cohort was randomly divided into a training cohort and a validation cohort. The influences of primary tumor site, localized and distant metastases, and sites and number of metastases on the prognosis of metastatic LMS patients were firstly explored by Kaplan–Meier curves and log-rank tests. Furthermore, the effective therapeutic regimens and prognosticators for metastatic LMS patients were also analyzed by Cox analysis. In addition, two prognostic nomograms for OS and CSS were established, and their predictive performances were evaluated by the methods of receiver operating characteristic (ROC) curves, time-dependent ROC curves, calibration curves, and decision curve analysis (DCA). A total of 498 patients were finally collected from the SEER database and were randomly assigned to the training set (N = 332) and validation set (N = 166). No significant differences in OS were observed in patients with distant organ metastasis and localized metastasis. For patients who have already developed distant organ metastasis, the sites and number of metastases seemed to be not closely associated with survival. Patients who received chemotherapy got significantly longer survival than that of their counterparts. In univariate and multivariate Cox analyses, variables of surgery, chemotherapy, age, and tumor size were identified as independent predictors for OS and CSS, and distant metastasis was also independently associated with CSS. The areas under the curve (AUCs) of ROC curves of the nomogram for predicting 1-, 3-, and 5-year OS were 0.770, 0.800, and 0.843, respectively, and those for CSS were 0.777, 0.758, and 0.761, respectively. The AUCs of time-dependent AUCs were all over 0.750. The calibration curves and DCA curves also showed excellent performance of the prognostic nomograms. Metastasis is associated with reduced survival, while the sites and the number of metastases are not significantly associated with survival. The established nomogram is a useful tool that can help to perform survival stratification and to optimize prognosis-based decision-making in clinical practice.

Comparison of clinicopathological features and outcomes in patients with primary leiomyosarcoma of bone and soft tissue

BACKGROUNDS AND OBJECTIVES

This investigation sought to describe the outcomes of primary leiomyosarcoma of bone (PLB) compared to soft tissue leiomyosarcoma (SLMS).

METHODS

This was a review of the Surveillance, Epidemiology, and End Results database from 1975 to 2016. Kaplan-Meier methods were used to estimate disease-specific survival (DSS), and a Cox regression model was used to identify prognostic factors.

RESULTS

Of the 7502 identifiable cases, 1% (n = 74) were PLB and 99% (n = 7428) were SLMS. Survival was the same between PLB and SLMS (p = .209). On multivariable analysis for high-grade SLMS, radiation (neoadjuvant: hazard ratio [HR], 0.56; 95% confidence interval [CI], 0.4-0.8; p = .003; adjuvant: HR, 0.75; 95% CI, 0.6-0.9; p = .008) and surgery (procedure specific) improved DSS. For PLB, wide resection/limb salvage (HR, 0.40; 95% CI, 0.3-0.5; p = .018) and amputation (HR, 0.69; 95% CI, 0.5-0.9; p < .001) were positive prognostic factors. Neither radiation nor chemotherapy were prognostic factors for survival in PLB.

CONCLUSIONS

For SLMS, radiation portends a survival advantage. For PLB, however, neither chemotherapy nor radiation were significant prognostic factors, which suggests the optimal treatment for PLB, similar to other primary soft tissue sarcomas originating in bone, remains an unmet medical need.

A rare case of orbital angioleiomyoma

A 65-year old woman presented with 3-year history of painless, gradual swelling of the right upper eyelid associated with proptosis. Computed tomography (CT) and magnetic resonance imaging (MRI) of the orbit showed a well circumscribed soft tissue mass in the supero-lateral orbit. An excision biopsy of the lesion was performed via lateral orbitotomy. Histopathology examination and immunochemistry staining confirmed the diagnosis of cavernous angioleiomyoma. The tumour was excised completely. Orbital angioleiomyoma is a rare benign tumour and the lesion can cause visual morbidity, particularly when intraconal. Despite sophisticated imaging modalities, histopathological analysis is essential for diagnosis. Angioleiomyoma should be included in the differential diagnosis of well-defined orbital lesions. Complete surgical excision carries a low risk of recurrence.

The 2020 WHO Classification of Tumors of Soft Tissue: Selected Changes and New Entities

Soft tissue tumors are a relatively rare and diagnostically challenging group of neoplasms that can have varying lines of differentiation. Accurate diagnosis is important for appropriate treatment and prognostication. In the 8 years since the publication of the 4th Edition of World Health Organization (WHO) classification of soft tissue tumors, significant advances have been made in our understanding of soft tissue tumor molecular biology and diagnostic criteria. The 5th Edition of the 2020 WHO classification of tumors of soft tissue and bone incorporated these changes. Classification of tumors, in general, but particularly in soft tissue tumors, is increasingly based on the molecular characteristics of tumor types. Understanding tumor molecular genetics improves diagnostic accuracy for tumors that have been difficult to classify on the basis of morphology alone, or that have overlapping morphologic features. In many large hospitals in the United States and Europe, molecular tests on soft tissue tumors are a routine part of diagnosis. Therefore, surgical pathologists should be familiar with newly emerging molecular genetic techniques in clinical settings. In the near future, molecular tests, particularly in soft tissue tumor diagnosis, will become as routine during diagnosis as immunohistochemistry is currently. This new edition provides an updated classification scheme and essential diagnostic criteria for soft tissue tumors. Newly recognized entities and subtypes of existing tumor types, several reclassified tumors, and newly defined molecular and genetic data have been incorporated. Herein, we summarize the updates in the WHO 5th Edition, focusing on major changes in each category of soft tissue tumor, and the newly described tumor entities and subtypes.

Calcified Leiomyoma of the Distal Forearm in a Child: A Case Report and Review of Literature

Background

Deep somatic leiomyomas arising in skeletal muscle are extremely rare in children, especially in the extremities. Around half of them show calcifications. We present a rare case of a calcified leiomyoma of the distal forearm in a child. Case Summary. A seven-year-old boy presented with right distal forearm and wrist pain with restricted supination for 4 years. X-ray showed ring and arc calcifications in the distal forearm at the interosseous area. MRI also confirmed a well-defined soft tissue lesion with areas of calcifications. A diagnosis of a cartilage-forming lesion or a peripheral nerve sheath tumour was suggested. The lesion was completely excised. Histology showed a lesion composed of intersecting fascicles of spindle cells with stromal calcification having immunohistochemical features of a leiomyoma.

Conclusion

Although soft tissue calcifications can be seen in a plethora of conditions seen in daily orthopaedic practise, a high index of suspicion should be maintained for rare conditions like deep somatic leiomyoma.

Retroperitoneal Sarcomas: An Update on the Diagnostic Pathology Approach

Retroperitoneal sarcomas are a heterogenous group of rare tumors arising in the retroperitoneum. Retroperitoneal sarcomas comprise approximately 10% of all soft tissue sarcomas. Though any soft tissue sarcoma histologic types may arise in the retroperitoneal space, liposarcoma (especially well-differentiated and dedifferentiated types) and leiomyosarcoma do so most commonly. Retroperitoneal sarcomas are diagnostically challenging, owing to their diversity and morphological overlap with other tumors arising in the retroperitoneum. An accurate diagnosis is necessary for correct management and prognostication. Herein, we provide an update on the diagnostic approach to retroperitoneal sarcomas and review their key histologic findings and differential diagnoses.

Smooth muscle tumors of the gastrointestinal tract: an analysis of prognostic features in 407 cases

Smooth muscle tumors represent the second most common mural mesenchymal neoplasm in the gastrointestinal tract, but established criteria for prognostic assessment of these tumors are lacking. A large cohort of surgically resected intramural gastrointestinal smooth muscle tumors from 31 institutions was analyzed to identify potential prognostic features. Pathologic features were assessed by expert gastrointestinal and/or soft tissue pathologists at each center. Immunohistochemical confirmation was required. A total of 407 cases from the esophagus (n = 97, 24%), stomach (n = 180, 44%), small bowel (n = 74, 18%), and colorectum (n = 56, 14%) were identified. Patients ranged in age from 19 to 92 years (mean 55 years), with a slight female predominance (57%). Mean tumor size was 5.4 cm, with the largest tumor measuring 29 cm. Disease progression following surgery, defined as local recurrence, metastasis, or disease-related death, occurred in 56 patients (14%). Colorectal tumors were most likely to progress, followed by small bowel and gastric tumors. None of the esophageal tumors in this series progressed. Receiver operator characteristic analysis identified optimal cutoffs of 9.8 cm and 3 mitoses/5 mm² for discriminating between progressive and non-progressive tumors. Histologic features strongly associated with progression by univariate analysis included moderate-to-severe atypia, high cellularity, abnormal differentiation (defined as differentiation not closely resembling that of normal smooth muscle), tumor necrosis, mucosal ulceration, lamina propria involvement, and serosal involvement (P < 0.0001 for all features). Age, sex, and margin status were not significantly associated with progression (P = 0.23, 0.82, and 0.07, respectively). A risk assessment table was created based on tumor site, size, and mitotic count, and Kaplan-Meier plots of progression-free survival for each subgroup revealed progression-based tiers. Based on our findings, it appears that nonesophageal gastrointestinal smooth muscle tumors measuring >10 cm and/or showing ≥3 mitoses/5 mm² may behave aggressively, and therefore close clinical follow-up is recommended in these cases.

Inflammatory leiomyosarcoma shows frequent co-expression of smooth and skeletal muscle markers supporting a primitive myogenic phenotype: a report of 9 cases with a proposal for reclassification as low-grade inflammatory myogenic tumor

Inflammatory leiomyosarcoma (ILMS) is a very rare soft tissue tumor that usually follows an indolent clinical course, but long-term follow-up studies are lacking. Recent publications primarily focused on its genetic profile characterized by a near haploid genome. One study also showed these tumors to have upregulation of genes known to be crucial for skeletal muscle differentiation. Nevertheless, immunohistochemical expression of skeletal muscle markers, as well as markers that would help to distinguish ILMS from a long list of relevant differential diagnostic entities, has not been extensively studied. Nine cases of ILMS were collected and stained by a broad IHC panel which, besides others, contained MyoD1, myogenin, and PAX-7. A subset of cases was also analyzed by 2 different NGS assays and by MDM2 fluorescence in situ hybridization. Five male and 4 female patients ranged in age from 25 to 54 years (mean, 36 years). The tumors showed a predilection for intramuscular sites of the lower limbs (n = 4) and back (n = 2), whereas the remaining 3 cases affected an unspecified skeletal muscle, lung, and omentum. Follow-up with an average length of 10.6 years (range 0.5-22) was available for 8 patients. The omental tumor spread locally within the abdominal cavity, but the patient has been free of disease 7 years after treatment. None of the 5 patients with somatic soft tissue tumors (and follow-up longer than 1.5 years) had either recurrence or metastasis. Immunohistochemical studies revealed a substantial expression of skeletal muscle markers in almost all cases. This phenotype coupled with a highly characteristic genotype and significantly more indolent clinical behavior as compared with conventional leiomyosarcoma of deep soft tissue offers a strong rationale to change the current nomenclature. Based on the clinicopathological features and gene expression profile, we propose the name low-grade inflammatory myogenic tumor.

Primary Renal Leiomyosarcoma Arising from Renal Vein: A Case Report of Rare Entity with Review of Literature

Primary renal sarcomas are extremely rare neoplasms accounting for about 1% of all malignant renal neoplasms. Among all the sarcomas of kidney, leiomyosarcoma is the most common histotype. The histogenesis of these tumors is unclear, and presumably, they arise either from renal capsule or smooth muscle of renal vessels or renal pelvis. We report a case of a 65-year-old woman, who presented with intermittent abdominal pain for 1 year. The correct diagnosis was established only after the histopathological analysis of the resected specimen. The poor prognosis borne by these tumors mandates a thorough evaluation of all renal masses with unusual gross and histomorphology.

Surgery plus chemotherapy improves survival of patients with extremity soft tissue leiomyosarcoma and metastasis at presentation

Purpose: Extremity soft tissue leiomyosarcoma (LMS) with metastasis is a rare disease with a poor prognosis. The purpose of our study was to define clinical features of extremity soft tissue LMS with metastasis as well as to identify multivariable predictors of survival. Methods: During 1973-2015, 239 patients with metastatic extremity soft tissue LMS were identified from the Surveillance, Epidemiology, and End Results (SEER) program database. The prognostic analysis was performed using the Kaplan-Meier method and a Cox proportional hazards regression model. Results: This group comprised 126 females (52.7%) and 113 males (47.3%), whose ages ranged from 8 to 95 years (median 67 years). The overall survival (OS) and cancer-specific survival (CSS) rates of the entire group at 3 years were 22.6% and 23.4%, respectively. The median OS and CSS were 14.0±1.5 and 15.0±2.3 months, respectively. Multivariate analysis revealed that tumor size >10 cm, no surgery and no chemotherapy were independent risk factors of decreased OS and CSS. Radiotherapy was not significantly associated with OS or CSS. Conclusion: Extremity soft tissue LMS patients who present with metastasis at diagnosis had a poor prognosis. Patients who performed surgery for primary tumors and chemotherapy had a better chance for prolonged survival.

Development and Validation of a Prognostic Nomogram for Extremity Soft Tissue Leiomyosarcoma

Background: Extremity soft tissue leiomyosarcoma (LMS) is a rare disease with a poor prognosis. The aim of this study is to develop nomograms to predict the overall survival (OS) and cancer-specific survival (CSS) of patients with extremity soft tissue LMS.

Methods: Based on the Surveillance, Epidemiology, and End Results (SEER) database, 1,528 cases of extremity soft tissue LMS diagnosed between 1983 and 2015 were included. Cox proportional hazards regression modeling was used to analyze prognosis and obtain independent predictors. The independent predictors were integrated to develop nomograms predicting 5- and 10-year OS and CSS. Nomogram performance was evaluated by a concordance index (C-index) and calibration plots using R software version 3.5.0.

Results: Multivariate analysis revealed that age ≥60 years, high tumor grade, distant metastasis, tumor size ≥5 cm, and lack of surgery were significantly associated with decreased OS and CSS. These five predictors were used to construct nomograms for predicting 5- and 10-year OS and CSS. Internal and external calibration plots for the probability of 5- and 10-year OS and CSS showed excellent agreement between nomogram prediction and observed outcomes. The C-index values for internal validation of OS and CSS prediction were 0.776 (95% CI 0.752–0.801) and 0.835 (95% CI 0.810–0.860), respectively, whereas those for external validation were 0.748 (95% CI 0.721–0.775) and 0.814 (95% CI 0.785–0.843), respectively.

Conclusions: The proposed nomogram is a reliable and robust tool for accurate prognostic prediction in patients with extremity soft tissue LMS.

Calcified leiomyoma of the deltoid: pathophysiology and imaging review

Leiomyomas are benign tumors of smooth muscle cells. Leiomyomas of somatic soft tissue are a specific class of leiomyoma believed to arise from the smooth muscle cells found in the walls of blood vessels and represent less than 4% of benign, somatic soft tissue tumors. Of the somatic soft tissue tumors, approximately one-third will become calcified. We report an intramuscular, calcified leiomyoma arising from the left deltoid of a 47-year-old Caucasian male. To the best of the authors' knowledge, this is the first reported case of a calcified, intramuscular leiomyoma of the deltoid. Imaging studies and patient presentation were initially suggestive of tumoral calcinosis or myositis ossificans. It was not until pathologic examination that the correct diagnosis of the calcified leiomyoma was made. Leiomyoma should be included in the differential diagnosis of calcified soft tissue masses. If excised with adequate margins, recurrence is unlikely.

A rare anal mass: anal leiomyoma presented as perianal fistula

Leiomyoma of the anal canal originating from the internal anal sphincter is an extremely rare clinical entity. Generally, it does not produce any clinical signs unless it is large enough to cause obstruction, discomfort, bleeding or pain. The diagnosis is often made incidentally during rectal examination due to other perianal disease or check-up. Herein we report a case of internal anal sphincter leiomyoma diagnosed unexpectedly during rectal examination in a patient with perianal fistula, and treated successfully with surgical excision. We present a review of the literature, the diagnostic strategies, differential diagnosis, prognosis and treatment modalities of this lesion.

Benign Smooth Muscle Tumors (Leiomyomas) of Deep Somatic Soft Tissue

Leiomyomas of deep soft tissue are extremely rare and should only be diagnosed following adherence to stringent histological criteria, namely, the absence of nuclear atypia and of coagulative tumor necrosis. Whether extremely low counts of, or even any, mitotic activity are acceptable when making a diagnosis of leiomyoma in deep soft tissue sites is controversial. The morphology and immunophenotype of smooth muscle tumors in deep soft tissue are similar to their counterparts irrespective of topography. It is interesting to note that leiomyomas of deep soft tissue (extremity and retroperitoneum) are often hyalinized/sclerosed and calcified. However, the prediction of their behavior and correct codification is dependent on thorough, meticulous search for mitoses and necrosis. Leiomyomas of deep soft tissue in the extremity should be devoid of mitoses and "significant" cytological atypia. An occasional larger, slightly pleomorphic cell in the midst of bland spindle cells, can be regarded as insignificant atypia. If any mitotic activity and several atypical cells are encountered in smooth muscle tumors of deep soft tissue of the extremity, it would be prudent to invoke the appellation of smooth muscle tumor of uncertain malignant potential and advocate wide local excision and follow-up.

Treatment with epigenetic agents profoundly inhibits tumor growth in leiomyosarcoma

Leiomyosarcomas are rare mesenchymal neoplasms characterized by a smooth muscle differentiation pattern. Due to the extremely poor prognosis in patients, the development of novel chemotherapeutic regimens remains critically important. In this study, multiple leiomyosarcoma cell lines, SK-UT1, SK-LMS1, and MES-SA were treated with varying doses of the DNA Methyltransferase Inhibitors (DNMTi) 5-azacitidine (Aza), 5-aza-2-deoxycytidine (DAC), and guadecitabine (SGI-110). The effect of these epigenetic modulators was measured using both in-vitro and in-vivo models.

Of the three epigenetic modulators, Guadecitabine was the most effective at decreasing cell survival in LMS cell lines. SK-UT1 was found to be the more sensitive to all three epigenetic modulators, while SK-LMS1 and MES-SA were more resistant. The contrast in sensitivity seen was also represented by the increase in apoptosis in Aza and guadecitabine. In parallel with Aza, guadecitabine was observed to also arrest the cell cycle.

Treatment with guadecitabine led to a decrease in growth across the spectrum of sensitivity in LMS cell lines, both in a delayed in vitro and in vivo model; in parallel experiments, apoptotic pathways were activated in sensitive and less sensitive lines. Additional studies are required to explore potential therapeutic applications and mechanisms for leiomyosarcoma treatment.

Diagnosis, Classification, and Management of Soft Tissue Sarcomas

BACKGROUND

Soft tissue sarcomas are challenging to oncologists due to their unique character, the infrequency of their occurrence, and the difficulties in predicting outcomes. Advances in imaging, as well as improvements in surgical techniques and adjunctive treatment methods, have improved care for patients with these unusual disorders.

METHODS

The various types of soft tissue tumors are defined, and the statistics for the Orthopaedic Oncology Group in relation to them are reviewed and compared with literature references.

RESULTS

The overall survival rate for 1,220 tumors treated at our institute from June 1972 to June of 2001 was 72%, with a wide range. Patients with leiomyosarcomas, clear cell sarcomas, and malignant fibrous histiocytomas had a poorer survival rate, while those with fibrosarcomas, liposarcomas, and neurofibrosarcomas fared better. Outcome was affected by patient age, tumor anatomic site, tumor stage, and a history of recurrence.

CONCLUSIONS

Competent imaging, predictive immunological and genetic studies, improved surgery, and newer methods of adjunctive and neoadjunctive treatment should result in improvements in outcomes for patients with these tumors.

STELLA collaborates in distinct mesendodermal cell subpopulations at the fetal-placental interface in the mouse gastrula

The allantois-derived umbilical component of the chorio-allantoic placenta shuttles fetal blood to and from the chorion, thereby ensuring fetal-maternal exchange. The progenitor populations that establish and supply the fetal-umbilical interface lie, in part, within the base of the allantois, where the germ line is claimed to segregate from the soma. Results of recent studies in the mouse have reported that STELLA (DPPA-3, PGC7) co-localizes with PRDM1 (BLIMP1), the bimolecular signature of putative primordial germ cells (PGCs) throughout the fetal-placental interface. Thus, if PGCs form extragonadally within the posterior region of the mammal, they cannot be distinguished from the soma on the basis of these proteins. We used immunohistochemistry, immunofluorescence, and confocal microscopy of the mouse gastrula to co-localize STELLA with a variety of gene products, including pluripotency factor OCT-3/4, mesendoderm-associated T and MIXl1, mesendoderm- and endoderm-associated FOXa2 and hematopoietic factor Runx1. While a subpopulation of cells localizing OCT-3/4 was always found independently of STELLA, STELLA always co-localized with OCT-3/4. Despite previous reports that T is involved in specification of the germ line, co-localization of STELLA and T was detected only in a small subset of cells in the base of the allantois. Slightly later in the hindgut lip, STELLA+/(OCT-3/4+) co-localized with FOXa2, as well as with RUNX1, indicative of definitive endoderm and hemangioblasts, respectively. STELLA was never found with MIXl1. On the basis of these and previous results, we conclude that STELLA identifies at least five distinct cell subpopulations within the allantois and hindgut, where they may be involved in mesendodermal differentiation and hematopoiesis at the posterior embryonic-extraembryonic interface. These data provide a new point of departure for understanding STELLA's potential roles in building the fetal-placental connection.

Leiomyoma of deep soft tissue mimicking calcific myonecrosis

Leiomyoma of deep soft tissue is an unusual entity reported in less than 60 cases in the English literature. The lesion is now accepted as a rare neoplasm. Leiomyomata of deep soft tissue have been divided into 2 groups, those occurring primarily in women in the retroperitoneum, histologically similar to leiomyomata of the uterus, and those occurring equally in both sexes in the somatic deep soft tissues. Irrespective of location, these lesions can demonstrate calcification, and even less commonly ossification. We report a unique case of a leiomyoma of deep soft tissue that mimicked the clinical and radiographic features of calcific myonecrosis, also a rare mass forming soft-tissue lesion. Clinical and radiographic information are often critical in the diagnosis of soft-tissue lesions; however, this case demonstrates that a lesion can deviate from the standard clinical and radiographic interpretations most commonly attributed to it.

Kidney Graft Leiomyosarcoma: A Case Report

BACKGROUND

Kidney transplant (KT) recipients have a higher incidence of malignancy than the general population. Smooth muscle tumors (SMT), including leiomyosarcoma, are rare in kidney transplant recipients, and most cases are associated with Epstein-Barr virus (EBV) infection.

CASE REPORT

A 57-year-old man received a deceased donor kidney transplant at the age of 53 years, with 5 human leukocyte antigen (HLA) mismatches. Before the transplantation, the patient was IgG positive for EBV viral capsid antigen (VCA), negative for IgM EBV VCA, and also negative for IgG EBV nuclear antigen (EBNA), suggesting a prior EBV infection. He received immunosuppressive induction with basiliximab, and maintenance with tacrolimus, mycophenolate mofetil, and prednisolone. Two years after transplantation, he had an acute cellular rejection episode treated with methylprednisolone. An increased graft size was found 4 years after transplantation. A computed tomographic scan showed 3 solid tumors involving the renal graft with extension to the perinephric fat; no secondary localizations were found. A nephrectomy of the graft was performed. The histologic diagnosis was a high-grade leiomyosarcoma. In situ hybridization for EBV was negative. Nine months after nephrectomy, local recurrence was diagnosed. The surgical approach was unsuccessful, and the patient died after a brief period.

CONCLUSION

Kidney leiomyosarcoma is a very rare clinical condition. Most of these neoplasms that arise in transplanted recipients are associated with EBV in tumor tissue. Only one case of renal graft leiomyosarcoma without EBV RNA in the tumor has been previously reported.

An Unusual Case of Abdominal Leiomyoma Presenting as a Free Lying Intraperitoneal Mass in an Elderly Gentleman

Introduction. Leiomyomas are common benign tumours of female reproductive tract and are rarely seen in extrauterine location. Case Report. We report an interesting case of a free lying abdominal leiomyoma presenting as a painless abdominal lump in an elderly gentleman. Discussion. Primary abdominal leiomyomas are uncommon and require surgical removal if symptomatic.

Practical Issues for Retroperitoneal Sarcoma

Background

Retroperitoneal sarcoma is rare. Using initial specimens on biopsy, a definitive diagnosis of histological subtypes is ideal but not always achievable.

Methods

A retrospective institutional review was performed for all cases of adult retroperitoneal sarcoma from 1996 to 2015. A review of the literature was also performed related to the distribution of retroperitoneal sarcoma subtypes. A meta-analysis was performed.

Results

Liposarcoma is the most common subtype (45%), followed by leiomyosarcoma (21%), not otherwise specified (8%), and undifferentiated pleomorphic sarcoma (6%) by literature review. Data from Moffitt Cancer Center demonstrate the same general distribution for subtypes of retroperitoneal sarcoma. A pathology-based algorithm for the diagnosis of retroperitoneal sarcoma is illustrated, and common pitfalls in the pathology of retroperitoneal sarcoma are discussed.

Conclusions

An informative diagnosis of retroperitoneal sarcoma via specimens on biopsy is achievable and meaningful to guide effective therapy. A practical and multidisciplinary algorithm focused on the histopathology is helpful for the management of retroperitoneal sarcoma.

Clinical and Sonographic Evaluation of a Lower Extremity Angioleiomyoma in a 52-Year-Old Woman

OBJECTIVE

The purpose of this case study is to describe the role of sonographic examination in the initial evaluation of an angioleiomyoma and to discuss the characteristic findings associated with this soft tissue mass.

CLINICAL FEATURES

A 52-year-old woman presented with a large, tender, erythematous mass on the anterolateral aspect of her right knee. Sonographic examination revealed a highly vascular mass within the subcutaneous tissues. Differential considerations included benign soft tissues masses such as angioleiomyoma and hemangioma.

INTERVENTION AND OUTCOMES

Surgical consultation was recommended. Excisional biopsy was performed. Histopathological examination confirmed the diagnosis of angioleiomyoma.

CONCLUSION

Although ultrasonographic findings of a superficial soft tissue mass may be nonspecific, when a highly vascular, well-defined, slow-growing mass is present, angioleiomyoma should be included in the differential diagnosis.

Targeted exome sequencing profiles genetic alterations in leiomyosarcoma

Leiomyosarcoma (LMS) belongs to the class of genetically complex sarcomas and shows numerous, often non-recurrent chromosomal imbalances and aberrations. We investigated a group of LMS using NGS platform to identify recurrent genetic abnormalities and possible therapeutic targets. Targeted exome sequencing of 230 cancer-associated genes was performed on 35 primary soft tissue and visceral (extra-uterine) LMS. Sequence data were analyzed to identify single nucleotide variants, small insertions/deletions (indels), and copy number alterations. Key alterations were further investigated using FISH assay. The study group included patients with median age of 64 years and median tumor size of 7 cm. The primary sites included retroperitoneal/intra-abdominal, extremity, truncal, and visceral. Thirty-one tumors were high grade LMS, while four were low grade. Losses of chromosomal regions involving key tumor suppressor genes PTEN (10q), RB1 (13q), CDH1 (16q), and TP53 (17p) were the most frequent genetic events. Gains mainly involved chromosome regions 17p11.2 (MYOCD) and 15q25-26 (IGF1R). The most frequent mutations were identified in the TP53 gene in 13 of 35 (37%) cases. FISH analysis showed amplification of the myocardin (MYOCD) gene in 5 of 25 (20%) cases analyzed. None of the four low grade LMS showed losses or mutations of PTEN or TP53 genes. Genetic complexity is the hallmark of LMS with losses of important tumor suppressor genes being a common feature. MYOCD, a key gene associated with smooth muscle differentiation, is amplified in a subset of both retroperitoneal and extremity LMS. Further studies are necessary to investigate the significance of gains/amplifications in the development of these tumors.

Prognostic factors in patients with recurrent or metastatic retroperitoneal leiomyosarcoma

AIMS

Factors that predict the prognosis of patients with recurrent or metastatic retroperitoneal leiomyosarcomas after treatment are uncertain.

MATERIALS & METHODS

Clinical and pathological data on 22 patients with retroperitoneal leiomyosarcomas who were treated by a multidisciplinary abdominal soft-tissue tumor group were analyzed retrospectively to identify prognostic factors for their progression-free survival (PFS).

RESULTS & CONCLUSION

The median PFS in the 22 patients was 9 months. Microvessel density in tumor tissues, which was evaluated via CD34 expression in 16 cases, and the presence of metastasis on admission were both found to be correlated with PFS in a Kaplan-Meier analysis, but not in a multivariate analysis. The multivariate analysis did, however, show that complete resection of tumors and the FNCLCC (Fédération Nationale des Centres de Lutte Contre Le Cancer) disease grade were independent factors predicting PFS.

Renal leiomyosarcoma with soft tissue metastasis: An unusual presentation

Primary renal sarcomas are exceptionally rare, constituting 1% of all malignant renal tumours. Since the prognosis for a renal sarcoma is particularly poor, differentiation from sarcomatoid renal cell carcinoma (RCC) is necessary. Histopathology and immunohistochemistry are the only modes of diagnosing these sarcomas as they have no specific features clinically and radiologically. We report a case of renal leiomyosarcoma which was clinically diagnosed as RCC. Histopathology revealed a spindle cell sarcoma and immunohistochemistry (IHC) confirmed a renal leiomyosarcoma. She also had a liver nodule and mass in the right side of neck and left arm. Biopsy from these sites revealed a similar morphology and IHC confirmed leiomyosarcoma. We report a case illustrating the rarity of this disease and its aggressive nature owing to fatal metastatic potential.

Extraskeletal chondroma on the sole of the foot

A 47-year-old female presented with a solitary mass located in the plantar region of her left foot. The mass, which she noticed 2 years ago, grew gradually and caused increasing pain when bearing weight. Physical examination showed a 3.5-cm diameter tender nonmobile mass with firm consistency in the midplantar region. Radiographs showed a ring-like calcification compatible with cartilage tissue. Magnetic resonance imaging revealed a lobulated mass with a hypointense signal on T1-weighted images and a hyperintense signal on T2-weighted images in the mid-substance of the plantar fascia. After a skin incision was performed, the mass was dissected from the skin and subcutaneous tissue. Then, a marginal excision was performed. The histological assessment reported chondrocytes within lacunae embedded in a chondroid matrix with focal calcification. The definitive diagnosis was extraskeletal chondroma. Plantar pain resolved within 3 months and no recurrence was found at the 1-year follow-up.

LEVEL OF EVIDENCE

Therapeutic Level IV, Case Report.

MRI, MDCT features, and clinical outcome of extremity leiomyosarcomas: experience in 47 patients

OBJECTIVE

To describe MRI, MDCT features, and clinical outcome of extremity leiomyosarcomas (LMS).

MATERIALS AND METHODS

In this IRB-approved, HIPAA-compliant retrospective study, we included 47 patients (23 women, 24 men; mean age: 55.3 years, range: 17-85 years) with pathologically confirmed extremity LMS seen at our adult tertiary cancer center between 2000 and 2012. MRI/MDCT of primary tumors in 23 patients and follow-up in all patients were reviewed by two radiologists in consensus. Clinical data were extracted from electronic medical records.

RESULTS

Primary tumors were distributed in bones (6 out of 47), deep soft tissues (24 out of 47), and superficial soft tissues (17 out of 47). On imaging (bone = 4, deep soft tissue = 11, superficial soft tissue = 8), compared with skeletal muscle, they were T1 iso-hypointense and T2 hyperintense. Bone LMS were metaphyseal tumors with cortical destruction (3 out of 4). Deep soft-tissue LMS were large with hemorrhage (7 out of 11) and necrosis (10 out of 11). Superficial soft-tissue LMS were relatively smaller, homogeneously enhancing (6 out of 8) tumors. Distant metastases developed in 32 out of 47 patients (bone LMS [6 out of 6], deep soft-tissue LMS [18 out of 24], superficial soft-tissue LMS [8 out of 17]), commonly to lung (29 out of 47) and bone (14 out of 47). At the time of writing, 22 out of 36 patients (bone LMS [4 out of 6], deep soft-tissue LMS [15 out of 24], superficial soft-tissue LMS [4 out of 17]) have died. There was no statistically significant correlation between metastatic disease and tumor size or grade.

CONCLUSION

Extremity LMS arise in bones and in the deep and superficial soft tissues, frequently metastasize to the lungs, and have a poor prognosis. Superficial LMS tend to have a better prognosis than bone or deep soft-tissue LMS.

Soft tissue sarcomas--new approaches to diagnosis and classification

The study of sarcoma pathology is a rapidly evolving field. The continued refinement of classic diagnostic techniques in conjunction with the molecular diagnostics has resulted in an abundance of data regarding this diverse and rare group of tumors. We anticipate that cutting edge technology including next generation sequencing will continue to further our understanding of saromagenesis and enable more precise classification and diagnosis of sarcomas in the future.

Extensively ossifying oral leiomyoma: a rare histologic finding

Oral leiomyoma are rare neoplasms of the oral cavity. Ossification within leiomyoma is not unusual but is mostly reported in leiomyoma of the deep soft tissue. Ossifying leiomyoma is extremely rare in the head and neck. We identified a total of three cases of extensively ossified leiomyoma in the head and neck in the literature including lesions in the lateral pterygoid muscle and orbit. To the best of our knowledge, only one case of extensively calcified leiomyoma has been reported in the oral cavity. We present two such rare cases of oral leiomyoma with extensive intratumoral calcifications and ossification. Ossified leiomyoma should be considered in the differential diagnosis of calcified or hard/firm soft tissue masses in the oral cavity.

Low-grade smooth muscle tumors of the primary and the secondary mullerian system: a proposed concept of multicentricity

Some patients with bland smooth muscle tumors in the uterus have synchronous or asynchronous smooth muscle tumors in the peritoneum and/or the retroperitoneum. It is usually assumed that the uterine tumor is the primary lesion, and the extrauterine neoplasm represents its metastasis. Thus, they are designated as low-grade leiomyosarcomas because they lack the diagnostic features of a conventional spindle cell leiomyosarcoma. Nineteen such cases were retrieved from the files of the Department of Pathology at The University of Texas M.D. Anderson Cancer Center, covering a period of 18 yr. Institutional Review Board approval was obtained before the initiation of this study. In addition, 31 cases of conventional uterine leiomyosarcomas of a high grade were reviewed for comparison. Clinicopathologic features such as patients' age, tumor location, histologic features, stage, treatment, and follow-up were recorded. Immunohistochemical stains for estrogen receptor (ER), progesterone receptor (PR), p53, Ki-67, and WT-1 were performed in the initially detected tumor and the subsequent neoplasm of all cases with available material in the low-grade group and selected cases in the high-grade group. Compared with high-grade leiomyosarcomas, the low-grade group cases were found at an early age (45 vs. 52.8 yr), had a longer median time of "recurrence" (42 mo for the low-grade group vs. 12 mo for high-grade leiomyosarcomas), longer median survival (165 mo for the low-grade group vs. 41 mo for the high-grade group), and a much better overall survival (84% vs. 13%). Three (16%) patients died of disease in the low-grade group versus 27 (87%) patients in the high-grade leiomyosarcoma group. We also found a difference in the location of the extrauterine tumors. Most cases of low-grade tumors were found in the pelvis, abdomen, or retroperitoneum, whereas most high-grade leiomyosarcomas involved the lung. In the low-grade tumors, there were some differences in the immunophenotype between the uterine and the extrauterine neoplasms, but in the high-grade tumors, there were no differences in the immunohistochemistry between the primary tumor and the metastasis. In addition to these differences between the 2 groups in the age of the patients, sites of recurrences, and the immunophenotype of the uterine and extrauterine tumor, neither the uterine nor the extrauterine low-grade lesions had histologic features of malignancy. On the basis of these differences, the possibility that the extrauterine lesions in the low-grade group represent independent primaries involving the secondary mullerian system is proposed.

Three cases of collagenous fibroma with rim enhancement on postcontrast T1-weighted images with fat suppression

Collagenous fibroma, also known as desmoplastic fibroblastoma, is a benign fibrous soft tissue tumor showing gradual growth, commonly without aggressive local infiltration. Today, preoperative radiological diagnosis is important to avoid over-treatment and unnecessary extensive procedures, but is difficult because diagnostic imaging findings for collagenous fibroma have not been established. We report MR imaging findings of three collagenous fibromas in correlation with their histopathology. The characteristic rim enhancement on post-contrast T1-weighted images with fat suppression was present in all three cases, and we consider this to represent the difference in vascularity between the outer capsule-like fibrous tissue and the inside of the tumor.

Myogenic tumors in children and adolescents

Neoplasms of striated and smooth muscle in children are a diverse group of neoplasms that have some unique aspects in contrast to these tumors in adults. Rhabdomyosarcoma is the most common soft tissue sarcoma of infancy and childhood and is relatively common in adolescents. In contrast, smooth muscle tumors are relatively rare, and the various types of rhabdomyoma and smooth and skeletal muscle hamartomas are very uncommon. In recent years, the understanding of the pathologic and genetic aspects of rhabdomyosarcoma has been enhanced by adjunct techniques, such as immunohistochemistry and cytogenetic or molecular genetic analysis. The current classification of rhabdomyosarcoma emphasizes the histologic-prognostic correlations. This article reviews the clinicopathologic features of striated and smooth muscle tumors with an emphasis on the unique aspects of these neoplasms in children and adolescents and the differential diagnosis.

Pelvic Leiomyosarcoma obstructing vaginal opening — case report

We present a 42-year-old female admitted for a 4 month history of increasing pelvic discomfort and pain. Clinical examination revealed a large tumor obstructing the vagina. Tumor markers (CA 125, CEA, AFP and CA 19-9), white blood cells and biochemical tests were all within the normal limits. Pelvic ultrasound and magnetic resonance imaging scan confirmed the presence of a large retroperitoneal/pelvic mass. The tumor was surgically excised and pathohistologically diagnosed as a well differentiated leiomyosarcoma, staged IB. Six years after surgery the patient is well and disease free.

Classification, molecular characterization, and the significance of pten alteration in leiomyosarcoma

Leiomyosarcoma is a malignant smooth muscle neoplasm with a complicated histopathologic classification scheme and marked differences in clinical behavior depending on the anatomic site of origin. Overlapping morphologic features of benign and borderline malignant smooth muscle neoplasms further complicate the diagnostic process. Likewise, deciphering the complex and heterogeneous patterns of genetic changes which occur in this cancer has been challenging. Preliminary studies suggest that reproducible molecular classification may be possible in the near future and new prognostic markers are emerging. Robust recapitulation of leiomyosarcoma in mice with conditional deletion of Pten in smooth muscle and the simultaneous discovery of a novel role for Pten in genomic stability provide a fresh perspective on the mechanism of leiomyosarcomagenesis and promise for therapeutic intervention.

Paratesticular leiomyoma with a der(14)t(12;14)(q15;q24)

While uterine leiomyomas are among the most common and best cytogenetically characterized solid tumors, leiomyomas at other sites are rare. Only two karyotypically abnormal leiomyomas in males have been reported to date, both of them with unspecific chromosome aberrations. We recently analyzed by G-banding a paratesticular leiomyoma, a tumor type not cytogenetically examined before, and found the pseudodiploid karyotype 46,XY,der(5)t(5;14)(q31;q24),der(14)t(12;14)(q15;q24). The leiomyoma cells demonstrated strong immunohistochemical nuclear expression of the HMGA2 protein, supporting a role of HMGA2 as the target gene in 12q14∼15 rearrangements. In uterine leiomyomas, the t(12;14)(q15;q24) is the most frequent translocation leading to overexpression of HMGA2, therefore it seems that a common pathogenetic pathway exists for benign smooth muscle tumors of both the female and male reproductive organs. The finding of this abnormality may help identify a scrotal tumor of uncertain biologic potential but with smooth muscle differentiation as benign.

Dermal Epstein Barr virus--associated leiomyosarcoma: tocsin of acquired immunodeficiency syndrome in two children

Although rare in childhood, a relatively high incidence of smooth muscle tumors are recognized in patients with AIDS, mainly in association with Epstein Barr virus (EBV) infection. Although EBV-associated smooth muscle tumors have been documented rarely in the subcutis of AIDS patients, dermal involvement has not been described to date. This report describes dermal EBV-associated leiomyosarcomas (EBV-LMS) with a nodular but superficial plaque-like appearance on the lower limbs of 2 males, 9 and 12 years old. Histopathological assessment of the excised lesions demonstrated hypercellular mitotically active dermal tumors with hyperchromatic spindle and round cells, arranged in short fascicles and sheets, with microfoci of necrosis. A smooth muscle immunophenotype, including prominent desmin immunopositivity, and positive EBV-encoded RNA in situ hybridization investigation confirmed a diagnosis of EBV-LMS. Subsequent HIV seropositivity and AIDS were confirmed in both patients. Both patients also had pulmonary tuberculosis and received antituberculous therapy. Patient 1 had a 3 cm re-excision of the prior tumor site. He received highly active antiretroviral therapy, completed 6 months of antituberculous therapy, achieved immune reconstitution and viral suppression and is tumor-free 2 years after tumor excision. Patient 2 died before further therapy. The immune status, presence, and appropriate therapy of co-existent systemic infection and highly active antiretroviral therapy in AIDS patients with EBV-LMS are crucial to a favorable outcome.

Clear Cell Tumors of Soft Tissue

Clear cell lesions of soft tissue include varying morphologic patterns and a range of clinical behaviors and prognoses. Benign lesions include perivascular epithelioid cell tumors, clear cell fibrous papule, and distinctive dermal clear cell mesenchymal tumor; malignant tumors include clear cell sarcoma, liposarcoma, and rare malignant perivascular epithelioid cell tumors. Clear cell variants of other benign and malignant soft tissue tumors include fibrous histiocytoma, atypical fibroxanthoma, myoepithelioma, leiomyoma and leiomyosarcoma, and rhabdomyosarcoma. Metastatic clear cell tumors, including renal cell carcinoma and adrenal cortical carcinoma, should be considered in the differential diagnosis and excluded through clinical history, imaging studies, and immunohistochemical stains.