Botryomycosis: a rare mimic of sarcoma as an initial presentation of acquired immunodeficiency syndrome.

Botryomycosis is a rare granulomatous response to chronic bacterial infection most frequently associated with Staphylococcus aureus. This disease, which predominantly affects immunocompromised patients, may present with cutaneous, visceral, or soft tissue manifestations. Soft tissue involvement typically has an aggressive mass-like appearance on imaging which can be concerning for malignancy. In immunocompromised patients, botryomycosis can resemble fungal infection both clinically and histologically; therefore, definitive diagnosis requires tissue sampling along with histological and microbiological analysis. Presented here is a 25-year-old man with an enlarging intramuscular soft tissue mass of the right forearm as his first presentation of undiagnosed acquired immunodeficiency syndrome (AIDS). MR imaging showed a mildly T2 hyperintense and enhancing mass with infiltrative margins extending through tissue planes. Biopsy of the mass revealed Staphylococcus aureus-associated botryomycosis, which improved with nonsurgical treatment employing antibiotics. Unfortunately, the patient subsequently expired from other manifestations of his new AIDS diagnosis. This case describes the MR and PET-CT appearance of botryomycosis and also underscores that infection can mimic sarcoma, particularly in the setting of immunodeficiency.

Primary Site Identification of Soft-Tissue Mass: Things to Know in MRI Assessment.

The spectrum of soft-tissue mass is varied, including neoplastic and nonneoplastic/inflammatory lesions. However, soft-tissue tumors have similar imaging findings and, therefore, the diagnosis of soft-tissue mass is challenging. Although careful assessment of the internal characteristics on imaging can often narrow the differential diagnoses, the differential diagnosis may be out of the question if identification of the soft-tissue mass origin is missed. The purpose of this article is to review the imaging findings and the essential anatomy to identify the primary site of the soft-tissue mass, and discuss the associated potential pitfalls. In order not to fall into a pitfall, recognition of characteristic imaging findings indicating the origin of the soft-tissue mass and anatomical knowledge of the normal tissue distribution are necessary. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3.

Pediatric chest wall masses: spectrum of benign findings on ultrasound.

A palpable finding along the chest wall is a frequent indication for pediatric US. Accurate identification of benign lesions can reassure families and appropriately triage children who need follow-up, cross-sectional imaging, or biopsy. In this pictorial essay, we review chest wall anatomy, illustrate US techniques and discuss key US imaging features of common benign lesions and normal variants.

Update of pediatric soft tissue tumors with review of conventional MRI appearance-part 1: tumor-like lesions, adipocytic tumors, fibroblastic and myofibroblastic tumors, and perivascular tumors.

There are numerous soft tissue tumors and tumor-like conditions in the pediatric population. Magnetic resonance imaging is the most useful modality for imaging these lesions. Although certain soft tissue lesions exhibit magnetic resonance features characteristic of a specific diagnosis, most lesions are indeterminate, and a biopsy is necessary for diagnosis. We provide a detailed update of soft tissue tumors and tumor-like conditions that occur in the pediatric population, emphasizing each lesion's conventional magnetic resonance imaging appearance, using the recently released 5th edition of the World Health Organization Classification of Soft Tissue and Bone Tumors as a guide. In part one of this review, pediatric tumor-like lesions, adipocytic tumors, fibroblastic and myofibroblastic tumors, and perivascular tumors are discussed. In part two, vascular lesions, fibrohistiocytic tumors, muscle tumors, peripheral nerve sheath tumors, tumors of uncertain differentiation, and undifferentiated small round cell sarcomas are reviewed. Per the convention of the WHO, these lesions involve the connective, subcutaneous, and other non-parenchymatous-organ soft tissues, as well as the peripheral and autonomic nervous system.

Update of pediatric soft tissue tumors with review of conventional MRI appearance-part 2: vascular lesions, fibrohistiocytic tumors, muscle tumors, peripheral nerve sheath tumors, tumors of uncertain differentiation, and undifferentiated small round cell sarcomas.

There are numerous soft tissue tumors and tumor-like conditions in the pediatric population. Magnetic resonance imaging is the most useful modality for imaging these lesions. Although certain soft tissue lesions exhibit magnetic resonance features characteristic of a specific diagnosis, most lesions are indeterminate, and a biopsy is necessary for diagnosis. We provide a detailed update of soft tissue tumors and tumor-like conditions that occur in the pediatric population, emphasizing each lesion's conventional magnetic resonance imaging appearance, using the recently released 5th edition of the World Health Organization Classification of Soft Tissue and Bone Tumors as a guide. In part one of this review, pediatric tumor-like lesions, adipocytic tumors, fibroblastic and myofibroblastic tumors, and perivascular tumors are discussed. In part two, vascular lesions, fibrohistiocytic tumors, muscle tumors, peripheral nerve sheath tumors, tumors of uncertain differentiation, and undifferentiated small round cell sarcomas are reviewed. Per the convention of the WHO, these lesions involve the connective, subcutaneous, and other non-parenchymatous organ soft tissues, as well as the peripheral and autonomic nervous system.

Epithelioid Sarcoma Presenting in the Thumb of a Child.

Epithelioid sarcoma (ES) is a high-grade, soft tissue tumor of mesenchymal origin that rarely occurs in children and is often misdiagnosed as a benign entity. We present the case of a 12-year-old girl with a delayed diagnosis of ES of the left thumb. Radiological examination showed possible calcinosis from inflammation or traumatic injury. However, histopathological and immunohistochemistry studies showed findings consistent with a diagnosis of ES. She was treated with amputation of the interphalangeal joint of the left thumb. This case highlights the clinical and pathologic correlation required for the appropriate diagnosis and treatment of patients with soft tissue masses.

Impact of tumour stage on the surgical outcomes of scapular chondrosarcoma.

PURPOSE: Chondrosarcomas are common primary bone tumours in adults, often affecting the flat bones. Oncologic outcomes are often tied to tumour grade; however, grade is only a factor in the aggressiveness of a tumor. Extracompartmental extension, or tumor stage, has been found to be predictive of a poor outcome in other flat bone chondrosarcomas; however, this relationship has not been identified in the scapula. The purpose of the current study was to analyze the impact of tumour stage on the outcome of patients with scapular chondrosarcoma. METHODS: Thirty-nine patients (26 males:13 females) with a mean age of 46 ± 17 undergoing surgical resection of a scapular chondrosarcomas were reviewed. Most patients had grade 1 (n = 24) tumors, with 26 (67%) having extracompartmental extension. The mean follow-up was eight years. RESULTS: The ten year disease-specific survival was 77%. High-grade tumours (HR 18.15, p < 0.01) were associated with death due to disease. The ten year local recurrence- and metastatic-free survival were 77% and 74%. Positive surgical margins (HR 8.85, p < 0.01) were associated with local recurrence, and local recurrence was associated with metastatic disease (HR3.37, p = 0.04). All disease recurrences and death due to disease occurred in patients with extracompartmental extension (p < 0.05). CONCLUSION: Extracompartmental extension was associated with a worse oncologic outcome in patients with scapular chondrosarcomas. Positive margins were associated with local recurrence, which was associated with metastatic disease; wide local excision with negative margins should be a goal for all patients, regardless of tumour grade.

Phosphaturic Mesenchymal Tumor of the Ankle: A Case Report and Review of the Literature.

We report the case of a phosphaturic mesenchymal tumor of the ankle; an extremely rare lesion that causes osteomalacia via paraneoplastic renal phosphate wasting. A 41-year-old man was referred to plastic surgery with a swelling over the anterior ankle, which had been increasing in size for 1 year. Focused ultrasound assessment was inconclusive, but excision biopsy demonstrated features in keeping with a phosphaturic mesenchymal tumor. Evidence of tumor-induced osteomalacia was subsequently identified on review of historical biochemistry. The patient was followed-up for 1 year with normalization of serum phosphate. In this case report, we present a discussion of the differential diagnosis for foot and ankle soft tissue lesions, and a review of the literature regarding the diagnosis and management of these tumors. Accurate identification of any soft tissue lesion on clinical examination alone is extremely challenging and excision biopsy should be considered in cases of diagnostic uncertainty.

Does Magnetic Resonance Imaging After Diagnostic Ultrasound for Soft Tissue Masses Change Clinical Management?

OBJECTIVES: To evaluate whether a follow-up magnetic resonance imaging (MRI) scan performed after initial ultrasound (US) to evaluate soft tissue mass (STM) lesions of the musculoskeletal system provides additional radiologic diagnostic information and alters clinical management. METHODS: A retrospective chart review was performed of patients undergoing initial US evaluations of STMs of the axial or appendicular skeleton between November 2012 and March 2019. Patients who underwent US examinations followed by MRI for the evaluation of STM lesions were identified. For inclusion, the subsequent pathologic correlation was required from either a surgical or image-guided biopsy. Imaging studies with pathologic correlations were then reviewed by 3 musculoskeletal radiologists, who were blinded to the pathologic diagnoses. The diagnostic utility of MRI was then assessed on the basis of a 5-point grading scale, and inter-reader agreements were determined by the Fleiss κ statistic. RESULTS: Ninety-two patients underwent MRI after US for STM evaluations. Final pathologic results were available in 42 cases. Samples were obtained by surgical excision or open biopsy (n = 34) or US-guided core biopsy (n = 8). The most common pathologic diagnoses were nerve sheath tumors (n = 9), lipomas (n = 5), and leiomyomas (n = 5). Imaging review showed that the subsequent MRI did not change the working diagnosis in 73% of cases, and the subsequent MRI was not considered to narrow the differential diagnosis in 68% of cases. There was slight inter-reader agreement for the diagnostic utility of MRI among individual cases (κ = 0.10) between the 3 readers. CONCLUSIONS: The recommendation of MRI to further evaluate STM lesions seen with US frequently fails to change the working diagnosis or provide significant diagnostic utility.

Quantitative peripheral computed tomography to measure muscle area and assess lean soft tissue mass in children.

BACKGROUND: Skeletal muscle is one of the main components of lean soft tissue mass (LSTM). Low levels in children affect locomotion, posture, and increase the risk of metabolic syndrome. AIM: (1) To evaluate the association between muscle cross-sectional area (MCSA) of the lower left leg measured by peripheral quantitative computed tomography (pQCT) and total LSTM; namely, total left leg and left lower leg LSTM assessed by dual-energy X-ray absorptiometry (DXA) in a group of children, (2) to examine if MCSA is a predictor of LSTM, (3) to determine the ability of pQCT to identify children with low LSTM. SUBJECTS AND METHODS: Lower left leg MCSA and LSTM were measured using pQCT and DXA, respectively, in 396 children. RESULTS: Statistically significant positive correlations were found between the lower leg MCSA - total LSTM (r² = 0.789), total leg LSTM (r² = 0.79), and lower leg LSTM (r² = 0.791) (p < .01). MCSA explained 64-68% of the variance in LSTM. Receiver operator characteristic (ROC) curves determined the capacity of the lower left leg MCSA to identify low LSTM in girls (AUC 0.95) and boys (AUC 0.87). CONCLUSIONS: Our results showed that lower left leg MCSA, measured using pQCT, could be a tool to predict low LSTM in children.

Surgical Management of Arteriovenous Malformation in the Foot: A Case Study.

Arteriovenous malformations are frequently found in the head and neck, and are occasionally associated with congenital syndromes. They are rarely reported in the foot and ankle; however, when encountered in these particular locations, they may become painful and interfere with ambulation. Because of the lack of literature on pedal arteriovenous malformations, they remain enigmatic when encountered clinically. They form as a result of atypical development of the vascular system during embryogenesis. The identification, diagnosis, and treatment of an arteriovenous malformation can be challenging, because it may present similarly to more frequent soft-tissue pathologies in podiatric practice. These include fibroma, lipoma, ganglion cyst, or proteinaceous cyst. They have unpredictable behavior and a high recurrence rate. Failure to recognize and treat an arteriovenous malformation appropriately could result in ulceration, hemorrhage, and amputation. The identification and diagnosis must be accompanied with a full vascular work-up to determine the magnitude, flow, and extent of the lesion. After vascular work up, conservative, and surgical treatment options can be explored. This is an unusual case report of an arteriovenous malformation of the plantar foot that was previously misdiagnosed, and later presented to our facility for a second opinion. The steps taken for identification, diagnosis, and treatment are discussed along with surgical technique for excision of an arteriovenous malformation with successful outcome at 1 year follow-up. This case report will provide clinicians with armamentarium for diagnosis, workup, and treatment, when considering arteriovenous malformation in the differential diagnosis.

Chondroid lipoma: multimodality imaging in a 9-year-old female.

Chondroid lipomas are rare, benign lipomatous tumors that occur most frequently in adults during the fourth decade of life. While a female predominance was observed in the initial series of 20 cases described in 1993, the subsequent 49 reported cases do not support a strong gender predilection. We report a case of a chondroid lipoma presenting in a 9-year-old female as a painless, enlarging, left gluteal mass. This is the second case to be reported in the first decade of life and the fourth pediatric case reported in the literature (age < 21). We review the imaging and pathology findings as well as present a comprehensive review of the current literature.

Diffuse skeletal muscle extramedullary plasmacytomas: a rare case and review of the literature.

Extramedullary plasmacytomas are rare neoplasms arising from proliferations of monoclonal plasma cells. In primary form, these malignancies occur without other sites of plasma cell disease. Secondary extramedullary plasmacytomas occur in association with multiple myeloma and may be discovered during initial intramedullary disease or may occur during multiple myeloma relapse. In very rare instances, secondary extramedullary plasmacytomas have multifocal skeletal muscle involvement. We present a case of multifocal skeletal muscle plasmacytomas in a 58-year-old man with shoulder-reduced range of motion, pain, and a history of previously treated multiple myeloma. To our knowledge, the patient's unique relapse presentation of torso and shoulder soft tissue masses and the vast extent of skeletal muscle involvement are unique to cases in the current literature. This case also has MRI findings of a muscular plasmacytoma with internal hemorrhage which has not been previously reported. This case report will review imaging features and clinical presentations of intramuscular extramedullary plasmacytomas. Since imaging surveillance for multiple myeloma relapse is commonly performed, radiologists should be aware of these uncommon relapsing features including multifocal intramuscular masses which may contain internal hemorrhage.

Mediastinal and hilar soft tissue mass-like lesions in congenital unilateral pulmonary vein atresia: A retrospective review of seven pediatric patients.

BACKGROUND: Congenital unilateral pulmonary vein atresia (CUPVA) is known to lead to the formation of an abnormal confluent mediastinal and hilar soft tissue mass, thoracic hypoplasia, and interlobular septal thickening on the affected side. The purpose of the present study is to investigate the frequency and severity of mediastinal soft tissue mass-like lesions and examine other abnormal findings associated with CUPVA. METHODS: We retrospectively reviewed seven children with CUPVA who underwent contrast-enhanced CT scans and measured the soft tissue mass volume in the bilateral mediastinum (affected and normal side). The location of abnormal soft tissue was divided into three anatomical sections (paratracheal, peribronchial, and the dorsal aspect of the left atrium). The relationships among soft tissue volume and anatomical section were statistically evaluated. Also, the presence of thoracic hypoplasia, small ipsilateral pulmonary arteries, interlobular septal thickening, and ground-glass opacities were investigated. RESULTS: In all cases, CT scans confirmed the presence of confluent soft tissue mass-like lesions in the affected mediastinum. The soft tissue volume on the affected side was 5.5-fold greater than the volume on the normal side (average: 18.0 cm3 and 4.25 cm3 respectively, P < 0.01). Thoracic hypoplasia and interlobular septal thickening were found in all patients. Small pulmonary arteries and ground-glass opacities were present in six of the seven patients. CONCLUSION: Abnormal mediastinal and hilar soft tissue is commonly found in patients with CUPVA. So, if we encounter the mediastinal soft tissue mass in patients with CUPVA, no further test will be indicated.

Anterolateral knee pain related to thrombosed lateral patellar retinaculum veins: Unusual anterolateral pain of the knee.

We describe the ultrasound (US) features of venous thrombosis involving the lateral patellar retinaculum (LPR) veins presenting as anterolateral knee pain. Four male patients, aged 16 to 35 years, were referred for lateropatellar pain with focal tenderness. In two cases, physical examination also demonstrated soft tissue swelling at the anterolateral aspect of the knee. In all four cases, US showed subcutaneous fat edema surrounding a thrombosis involving the LPR veins. Magnetic resonance imaging performed before US in one patient revealed only nonspecific subcutaneous fat edema and was therefore unable to make the correct diagnosis of LPR venous thrombosis.

Primary Tumoral Calcinosis in a Pediatric Patient: A Rare Presentation.

Tumoral calcinosis is a benign, progressive disorder characterized by massive periarticular deposition of calcium salts into subcutaneous and deeper tissue layers. While a majority of cases present secondary to underlying metabolic disorders, it can rarely present as a primary, idiopathic phenomenon. We present an atypical case of a pediatric patient with a large, ulcerated pedal soft tissue mass found to be consistent with primary tumoral calcinosis. This was confirmed by histopathologic analysis and comprehensive metabolic workup. The patient underwent surgical excision of the mass, with complete resolution of symptoms and no recurrence after a 1-year follow-up period.

Elastofibroma in the Rearfoot: A Case Report of a Rare Soft Tissue Tumor.

An elastofibroma is a rare, benign, slow-growing, progressive soft tissue neoplasm with distinct histopathological features consisting of collagen and coarse elastic fibers. When it occurs, it has a propensity for the subscapular region in elderly female patients. It can occur less commonly at other anatomical sites, and its exact etiology is unclear. The incidence of elastofibroma, especially in the foot, has been sporadically reported; however, the presentation of elastofibroma in the rearfoot has not been previously described in the literature. We present the first report of a 79-year-old female presenting with plantar heel pain secondary to an elastofibroma found at the insertion of the plantar fascia into the calcaneal tuberosity. The patient underwent surgical excision, and pathological analysis revealed the diagnosis of elastofibroma. We discuss the peculiar manifestation of elastofibroma in this case, the pathological diagnosis, and a review of the literature.

Small soft tissue masses indeterminate at imaging: histological diagnoses at a tertiary orthopedic oncology clinic.

OBJECTIVE: To review histologic diagnoses of soft-tissue masses (STMs) ≤ 2 cm with indeterminate imaging features encountered in musculoskeletal oncology clinic at a tertiary referral center. MATERIALS AND METHODS: This was an IRB-approved retrospective review of patients with STMs ≤ 2 cm, referred to our tertiary care orthopedic oncology clinic over 4.75 consecutive years. Maximum diameter was based on imaging measurement by a fellowship-trained musculoskeletal radiologist. Simple lipomas, synovial cysts, metastases, and cases without histologic confirmation were excluded. Patient demographics, tumor imaging features (location, depth, size, and tumor:muscle enhancement and T2 signal ratios), and histology were recorded and compared. RESULTS: Mean maximum diameter for 42 trunk/extremity STMs was 1.5 cm (range, 0.7 to 2 cm). Mean age was 48 years (range, 18-83 years). Nine (21%) of the masses were malignant, while 33 (79%) were non-malignant. Thirty-nine (93%) of masses were superficial; 7/39 (18%) of these superficial tumors were malignant. Malignancy was not associated with underlying vessels, tendon, or fascia (p = 0.19). The non-malignant vs. malignant tumor:muscle enhancement ratio was 2.15 vs. 2.32 (p = 0.58) and enhancement coefficient of variation was 0.14 vs. 0.10 (p = 0.29). Most common malignant histologic subtypes were synovial sarcoma (n = 3), fibroblastic/myofibroblastic sarcoma (n = 2), leiomyosarcoma (n = 2), myxofibrosarcoma (n = 1), and angiomatoid fibrous histiocytoma (n = 1). The majority (67%) of non-malignant lesions were: leiomyoma (n = 6), angiomyoma (n = 5), schwannoma (n = 4), benign fibrous histiocytoma (n = 4), and hemangioma (n = 3). CONCLUSIONS: At a tertiary musculoskeletal oncology referral clinic, primary STMs ≤ 2 cm with indeterminate imaging features should be managed cautiously despite their small size and/or superficial location.

Extremity gossypiboma mimicking sarcoma: case report and review.

A 70-year-old man with a history of bladder and colon cancer presented with an enlarging mass in his right lower extremity. Forty years before presentation, he had injured his right lower extremity in a motor vehicle accident. Imaging findings indicated suspected sarcoma, which led to biopsy. Biopsy and further surgical exploration revealed the presence of a surgical sponge and surrounding local inflammatory reaction. No neoplasm was found, and the sponge and involved tissues were removed. Gossypiboma is exceedingly rare in the extremities. Imaging of retained foreign material can appear suggestive of sarcoma because of strong inflammatory responses and local tissue mass-like derangement resulting in heterogeneous signal changes. Ultimately, biopsy must be performed to ensure that no oncological pathological condition is present.

Prenatal sonography of multicentric infantile myofibromatosis: Case report and review of the literature.

Scant literature exists on prenatally diagnosed infantile myofibromatosis (IM). We report a case of multicentric IM, which was first recognized as a soft-tissue paraspinal mass on prenatal sonography and subsequently characterized by MRI with pathological confirmation.