Farzin Eftekhari

Clinical and radiologic review of the normal and abnormal thymus: pearls and pitfalls.

At imaging, the thymus appears in a variety of shapes and sizes, even in the same individual. It gradually involutes with age and may acutely shrink during periods of bodily stress. During the recovery period, it grows back to its original size or even larger, a phenomenon known as thymic rebound hyperplasia. These anatomic variations and dynamic changes appear to be the main source of confusion with pathologic conditions. In turn, these misinterpretations may lead to prolongation or alteration of the chemotherapy regimen or to unnecessary radiation therapy, biopsy, or thymectomy. Familiarity with the embryology, anatomy, and dynamic physiology of the thymus is essential to avoid unnecessary imaging or invasive procedures. Radiologists play a major role in differentiating normal thymic variants, ectopic thymic tissue, and nonneoplastic thymic conditions such as rebound hyperplasia from neoplastic conditions. Knowledge of the imaging findings of thymic tumors and their mimics may help radiologists arrive at the correct diagnosis.

Can cure in patients with osteosarcoma be achieved exclusively with chemotherapy and abrogation of surgery

Contemporary therapy for osteosarcoma is comprised of initial treatment with chemotherapy and surgical extirpation of the primary tumor in the affected bone. In view of the major advances forged by chemotherapy in the treatment of the primary tumor, an attempt was made to destroy the tumor exclusively with this therapeutic modality and abrogate surgery.

Cystic retroperitoneal lymphangioma: CT, ultrasound and MR findings

A case of cystic retroperitoneal lymphangioma complicated by hemorrhage is reported in a 7-year-old boy who presented with an abdominal mass. The mass which was partially obstructing the ureter was successfully resected. The imaging findings with emphasis on MR features are described.

Chemotherapy of locally aggressive head and neck tumors in the pediatric age group: Desmoid fibromatosis and nasopharyngeal angiofibroma☆

Our experience with the use of systemic chemotherapy in the management of locally aggressive head and neck tumors in the pediatric age group (desmoid fibromatosis and nasopharyngeal angiofibroma) is presented. Objective decreases in the size of tumors was found in all patients with desmoid fibromatosis was treated with chemotherapy before definitive surgical resection was performed. The changes noticed on examination correlated with the histologic and radiologic findings. Two patients with recurrent juvenile nasopharyngeal angiofibromas showed striking therapeutic improvement in their residual tumor mass as witnessed by radiographic studies and biopsies. Toxicity and side effects of the treatment are discussed.

Merkel cell carcinoma of the skin: imaging and clinical features in 93 cases

Clinical, pathological and imaging data for 93 patients with Merkel cell carcinoma were reviewed. Median survival duration from the date of diagnosis was estimated using the Kaplan-Meier product-limit method. Survival durations of patients with no metastastic disease, with regional lymph node metastasis only and with distant metastases were compared using the Cox-Mantel log-rank test. The median age for patients with Merkel cell carcinoma was 70 years (range 35-91 years). The tumour occurred in 71 men and 22 women. The most common primary site was the head and neck region (64 patients), followed by the extremities (21 patients) and the trunk (10 patients). Median survival duration for the whole group was 33 months (range 2-140 months). Imaging studies of the primary sites were available for 10 patients and of metastatic sites for seven patients. Sonograms of the primary skin lesions showed single or multicentric hypoechoic nodules arising from the dermis and growing into the subcutaneous tissues. CT scans showed single or multiple minimally enhancing soft tissue nodules, in two instances associated with lytic bone erosion. The metastatic lesions were moderately hypoechoic on sonography and target-shaped with or without ring-enhancement on CT. Imaging studies have a limited role in diagnosis of the clinically evident primary skin lesions, but may be helpful in the assessment of the depth of the invasion and are crucial in the evaluation of regional and distant metastatic disease. If regional adenopathy is found then CT of the chest, abdomen and pelvis may be in order.

Mesenchymal hamartoma of the chest wall in infants and children: a clinicopathological study of five patients

Mesenchymal hamartoma of chest-wall is a rare benign lesion that has varied histological characteristics and usually occurs during early infancy. We report the histological characteristics of mesenchymal hamartoma found in five patients aged respectively 25 days, 5 months, 8 months, and 4 and 8 years at presentation. Two patients presented with respiratory distress, two with an asymptomatic chest-wall mass, and one with a deformity of the left chest wall. Surgical resection was performed on four patients and a biopsy only in one patient. Overall, the tumors were well delineated, lobulated, tan to reddish in color, and on section showed bloodfilled cystic spaces with interspersed small islands of cartilage and fibrous tissue. Histological analyses demonstrated mixtures of bone trabeculae with spindle-cell stroma, chondroblast-like proliferation, mature and immature hyaline cartilage, and aneurysmal bone cyst formation. All patients are alive and well without evidence of disease. Despite the alarming clinical and histologic presentation, mesenchymal hamartoma of the chest wall is a non-neoplastic benign lesion.

Fibrous hamartoma of infancy: Mr-pathologic correlation

AbstractWe report a case of fibrous hamartoma of infancy, a rare benign tumor, in which MR findings remarkably paralleled the well-defined histologic features characteristic of this tumor, namely fibrous tissue and fat.

Intraarterial management of giant-cell tumors of the spine in children

Transcatheter arterial management of giant cell tumors of the spine was performed in two female patients aged 12 and 15 who had failed to respond to conventional therapy. Response was determined clinically by alleviation of pain and radiographically by regression and/or calcification of the tumor. Minor side effects included transient nausea, elevated body temperature, and pain.

Sonographic findings in Richter's hernia.

Richters hernia can present as a diagnostic challenge because of its usually small size and eccentric bowel wall involvement with limited luminal compromise. This article describes a case of Richters hernia in the femoral canal and illustrates its sonographic features.

Imaging Assessment of Osteosarcoma in Childhood and Adolescence: Diagnosis, Staging, and Evaluating Response to Chemotherapy

Osteosarcoma is an aggressive tumor of mesenchymal origin, capable of producing osteoid and immature bone. It is the most frequent primary malignant skeletal neoplasm in children and adolescents. Imaging studies play a major role in initial diagnosis, staging, and assessment of tumor response to chemotherapy. Conventional radiography is the prime imaging modality for diagnosis of bony tumors. Radionuclide bone scan is used in detection of metastatic lesions in the other bones. Computed tomography may be used as an adjunct to conventional radiography, but its main role is detection of pulmonary metastasis. The standard magnetic resonance imaging is the most specific modality for local staging and monitoring response to chemotherapy, and distinguishing postsurgical changes from residual tumor. Dynamic contrast-enhanced magnetic resonance imaging has been introduced to quantify the percentage of tumor necrosis, identify early responders, and thus predict survival. The role of 18F fluorodeoxyglucose positron emission tomography (PET) in the staging and management of osteosarcoma is evolving. It has the advantage of total body imaging and may have an overall role in tumor staging and grading, detection of early response, and therefore, in the prognosis and detection of recurrence.