Imaging of primary multifocal osseous lymphoma

 Objective. To review our experience with primary multifocal osseous lymphoma (PMOL), to characterize its imaging features, before and after treatment, and to correlate these features with clinical outcome. Design. Hospital charts and imaging studies of eight patients with PMOL were reviewed. These included bone radiographs, bone scans, CT and MRI. Number, distribution and appearance of lesions before treatment were evaluated; and post-treatment changes were assessed for evidence of healing or progression, correlated with clinical outcome. Results. A total of 63 lesions were identified by pre-treatment bone scan, 36 by MRI (including 10 not visible on bone scan) and 16 by radiographs. Twenty-one percent of lesions occurred about the knee, and 63% of patients had concomitant skull, distal femoral and proximal tibial lesions. The radiographic appearance ranged from lytic to sclerotic. Lesions were isointense to hematopoietic marrow on T2-weighted MR sequences. Only plain radiographic evidence of healing or progression correlated with clinical outcome. Conclusion. Distribution of PMOL was best assessed by bone scan. However, MRI revealed larger areas of marrow involvement and detected lesions in the pelvis not seen on bone scan. Marrow involvement around the knee was common, and the combination of skull, distal femoral and proximal tibial lesions may suggest the diagnosis. Radiographs underestimate the extent of disease but were the best modality for assessment of treatment response.     

Epithelioid sarcoma of the median nerve mimicking a peripheral nerve sheath tumour

We describe a case of epithelioid sarcoma of the median nerve in a 57-year-old woman presenting with symptoms and signs of carpal tunnel syndrome for 2 years. The clinical examination was suggestive of a wrist ganglion compressing the median nerve. Magnetic resonance imaging (MRI) showed a 5 cm x 3 cm mass involving the median nerve in the carpal tunnel and appearances mimicked a benign peripheral nerve sheath tumour. This report illustrates a rare tumour presenting in a rare location and emphasizes the atypical clinical and MRI features that should alert the radiologist to the possibility of a rare sarcoma mimicking a benign peripheral nerve sheath tumour.     

Epithelioid sarcoma mimicking abscess: review of the MRI appearances

A case of epithelioid sarcoma involving the soft tissues of the ankle is presented. The tumor was a hemorrhagic, fluid-filled, multiloculated lesion with inflammatory changes in the surrounding planes. Tuberculous abscess was diagnosed on the basis of the clinical picture, ultrasound and MRI findings. Surgical exploration of the ankle mass was carried out because of lack of local healing while the patient’s general and pulmonary status improved on antituberculosis treatment. This was an unusual case of epithelioid sarcoma mimicking a multilocular abscess. Received: 11 October 1999 Revision requested: 2 November 1999 Revision received: 30 October 2000 Accepted: 3 November 2000     

Epithelioid sarcoma with unusual radiological findings

 The case of a patient with epithelioid sarcoma in the right arm is reported. The diagnosis was delayed because of misinterpretation arising from complexity in the MR findings, including a honeycomb pattern in the subcutaneous fat simulating lymphedema, and an intramuscular diffuse high signal intensity on T2-weighted images without a discrete mass lesion. The histological findings revealed that the diffuse muscular abnormality mainly resulted from denervation of the muscles due to perineural invasion by the tumor, and subcutaneous edema from lymphedema secondary to lymphatic tumor spread concurrent with lymphatic fibrosis. Multiple foci of cortical erosions in the humerus, a rare manifestation of this tumor, were detected 6 months later.     

Congenital spleen thinning mimicking a space-occupying lesion

By splenic imaging, a large focal defect was demonstrated in a symptomatic South American immigrant with simultaneous parasitic infestation of strongyloidiasis and entamebiasis. The CT scan also was thought to be abnormal. Pathologic findings reported a variation in splenic configuration. Unusual splenic configuration should be considered in the differential diagnosis of abnormal scans.     

肩胛骨尤文肉瘤1例

患者男,7岁.3 d前发现右肩部肿块,小的似鸡蛋大小,大的似小碗口大小,质硬无活动,边界不清,无红肿压痛,局部皮温不高,无表浅静脉怒张.其他部位检查未见明显异常.超声检查:右肩背部皮下肌肉探及约25 cm×20 cm×5 cm低回声区,边界尚清,内部回声不均匀,彩色多普勒血流显像(CDFI)检查示丰富血流信号,脉冲多普勒(PWD)可测及动、静脉频谱.     

Epithelioid hemangioendothelioma mimicking a nerve sheath tumor clinically and on MR imaging

Epithelioid hemangioendothelioma is a tumor of the soft tissues arising from the vascular endothelium. It is considered an intermediate grade malignancy. A 42-year-old female patient presented with pain and tingling down her right arm and a mass at the right medial upper extremity. MRI revealed an oblong mass along the course of the neurovascular bundle. Given the clinical and MR findings, a nerve sheath tumor was suspected. At surgery, the mass was adherent to both the brachial artery medially and the median nerve posteriorly. Pathology revealed epithelioid hemangioendothelioma. The imaging characteristics of epithelioid hemangioendothelioma on ultrasound, CT, and MRI are reviewed. Epithelioid hemangioendothelioma can mimic a nerve sheath tumor clinically and radiologically and should be considered in the differential diagnosis of tumors involving or adjacent to a neurovascular bundle.     

Sarcoidosis breaching the fascia and mimicking a sarcoma

A 55-year-old woman complained of a subcutaneous mass in her left buttock. MR images revealed an ill-defined soft tissue mass that crossed the fascia of the gluteus maximus muscle. Some surrounding edema was noted. The lesion showed some contrast uptake after administration of Gd-DTPA. An excisional biopsy revealed sarcoidosis involving both the muscle and subcutaneous tissue across the fascia, mimicking a sarcoma.     

Epithelioid sarcoma:radiologic and pathologic manifestations.

The radiologic and pathologic manifestations of epithelioid sarcoma are presented based on an analysis of five cases, and the literature is reviewed. This rare entity tends to orginate in the extremities and metastasizes primarily via the lymphatics. Although the lesion grows slowly, it recurs with high frequency. Males are affected three times as often as females. The differential diagnosis includes both malignant and benign entities. The natural history and methods of treatment are reported.     

Pedunculated bronchogenic cyst mimicking pleural lesion

We report a rare case of a bronchogenic cyst presenting as a pleural nodule. CT and MRI demonstrated a well circumscribed, homogeneous lesion located on the pleural surface apart from the mediastinum. It was proven to be a bronchogenic cyst localized between the parietal and visceral pleurae and connected with the mediastinum only through fibrous tissue. Radiologists should be aware that a mediastinal bronchogenic cyst may be located apart from the mediastinum.     

Periprostatic schwannoma mimicking metastatic lymphadenopathy in a case of multifocal prostate adenocarcinoma

Schwannomas of the prostate are a rare entity and usually diagnosed incidentally following surgical management of presumed benign prostate hyperplasia or prostate adenocarcinoma. We present a case of sporadic periprostatic schwannoma diagnosed in conjunction with multifocal prostate adenocarcinoma on pre-operative multiparametric magnetic resonance imaging.     

Generalized intramuscular granulocytic sarcoma mimicking polymyositis

We report a case of granulocytic sarcoma exclusively manifesting as diffuse intramuscular infiltration of the proximal upper and lower limb girdle and the torso muscles in a patient with previous history of acute myelogenous leukemia 5a. Whole-body CT showed widespread distribution of ill-defined intramuscular, homogeneously enhancing lesions. On whole-body MRI, lesions were homogeneously hyperintense on fat saturated T2-weighted images, isointense on T1-weighted images and strongly enhancing after intravenous gadolinium contrast administration. Histopathology revealed muscular infiltration of blast cells with identical immunochemistry to the initial manifestation of leukemia, diagnostic for an extramedullary relapse manifesting as granulocytic sarcoma. CT and MRI characteristics of this previously undocumented manifestation of granulocytic sarcoma should assist in the identification of such cases.     

Enchondroma: a benign osseous lesion with high F-18 FDG uptake

A woman was referred for fluorodeoxyglucose positron emission tomography for the staging of a malignant melanoma. Although no signs of metastatic melanoma were evident on the whole-body scan, focally increased uptake within the femoral metaphysis was noted. Radiographic and magnetic resonance examinations revealed an enchondroma as the cause of the increased uptake. Histopathologic verification was obtained. The final diagnosis was actively proliferating enchondroma. A grade I chondrosarcoma could be ruled out. Enchondromas may be responsible for focally increased FDG uptake in bone lesions and must be considered when positron emission tomographic scans obtained with FDG are evaluated in cancer staging.     

Epithelioid sarcoma: clinical,MR imaging and pathologic findings

OBJECTIVE: To report and describe the MR imaging features of eight new cases of this rare soft tissue sarcoma and correlate them with the clinical and histologic findings.DESIGN AND PATIENTS. Retrospective analysis was carried out for the MR imaging characteristics and histologic findings of eight patients with pathologically proven epithelioid sarcoma and the literature was reviewed. Findings were correlated in each case with the patient's clinical presentation and eventual outcome.RESULTS: The patients, whose primary tumors ranged from 2.5 cm to 19 cm in maximum dimension, were 1 to 90 years of age. Tumors involved the extremities ( n=5), the scalp ( n=2) and the paraspinal muscles ( n=1). Five tumors presented as well-defined, frequently painful, deeply situated masses and three as subcutaneous nodules or cutaneous ulcers with no palpable mass. Four patients had associated regional lymphadenopathy and one had distant metastases at diagnosis. MR imaging showed tumor infiltration of adjacent tissues in seven patients. Signal characteristics reflected varying degrees of cellularity, and the presence of necrosis, hemorrhage, fibrosis, hyalinization and inflammation. Bone marrow involvement was demonstrated in one patient. Clinical outcomes were generally poor.CONCLUSIONS: Epithelioid sarcoma is an aggressive soft tissue sarcoma with a varied clinical presentation, growth pattern, MR signal characteristics and histologic picture. The tumor favors the distal extremities and is commonly infiltrative and accompanied by enlarged regional lymph nodes. This neoplasm may present as an intramuscular mass but should also be suspected in patients with ulcerating cutaneous nodules with or without regional lymphadenopathy.     

COVID-19 vaccine-associated ganulomatous mass mimicking a sarcoma: a case report

Several studies have previously documented the development of complications stemming from injection with one of the various COVID-19 vaccines. No study, however, has discussed the spontaneous development of a soft tissue mass shortly after a COVID-19 vaccine injection. We report on 66-year-old female with concerns of a growing shoulder mass, 2 weeks after receiving a COVID-19 vaccine booster. Initial work-up with X-ray and MRI was concerning for a soft tissue neoplasm, specifically a soft tissue sarcoma. Subsequent ultrasound guided biopsy demonstrated a benign granulomatous lesion. No further management was required as the lesion spontaneously resolved during a 3-month follow-up period.