Arpit Nagar

Mesenchymal Neoplasms of the Kidney in Adults: Imaging Spectrum with Radiologic-Pathologic Correlation

Mesenchymal neoplasms of the kidney in adults cover a wide spectrum with characteristic ontogeny and histologic findings and variable biologic profiles and imaging findings. Benign mesenchymal renal tumors include angiomyolipoma, leiomyoma, hemangioma, lymphangioma, juxtaglomerular cell tumor, renomedullary interstitial cell tumor (medullary fibroma), lipoma, solitary fibrous tumor, and schwannoma. Malignant renal tumors of mesenchymal origin include leiomyosarcoma, rhabdomyosarcoma, angiosarcoma, osteosarcoma, synovial sarcoma, fibrosarcoma, malignant fibrous histiocytoma, and solitary fibrous tumor. Cross-sectional imaging findings for mesenchymal renal tumors in adults are varied. Although angiomyolipomas and lipomas show macroscopic fat, lymphangiomas are cystic in appearance. Renal hemangioma may show phleboliths and a characteristic enhancement pattern. Leiomyoma typically arises from the capsule and causes buckling of the renal cortex. Although osteosarcoma may demonstrate characteristic dense ossification, most renal sarcomas demonstrate imaging features that are indistinguishable from the more common renal cell carcinoma. Although some renal mesenchymal tumors have typical imaging findings, biopsy is warranted to establish a definitive diagnosis. Awareness of the various mesenchymal renal tumors and familiarity with their imaging findings permit optimal patient management.

Neoplastic and non-neoplastic proliferative disorders of the perirenal space: cross-sectional imaging findings.

The perirenal space, located between the anterior and the posterior renal fasciae, is shaped like an inverted cone with an apex that extends into the iliac fossa. Perirenal tumors and pseudotumors primarily originate either from the kidney or as part of a systemic disease process and have characteristic histopathologic features and biologic behavior. The lesions may be classified on the basis of their distribution and imaging features as solitary soft-tissue masses (renal cell carcinoma, lymphangioma, hemangioma, and leiomyoma), rindlike soft-tissue lesions (lymphoma, retroperitoneal fibrosis, and Erdheim-Chester disease), masses containing macroscopic fat (angiomyolipoma, liposarcoma, myelolipoma, and extramedullary hematopoiesis), and multifocal soft-tissue masses (metastases, plasma cell tumors). Because of overlap in imaging findings among these diverse perirenal lesions, a definitive diagnosis in most cases can be established only at histopathologic analysis. However, an imaging pattern-based approach may facilitate the diagnosis and optimal management of perirenal tumors and pseudotumors.

Current Update on Borderline Ovarian Neoplasms

OBJECTIVE Borderline ovarian tumors comprise a unique group of noninvasive ovarian neoplasms with characteristic histology and variable tumor biology that typically manifest as low-stage disease in younger women with resultant excellent prognosis. CONCLUSION Borderline tumors are considered to be precursors of low-grade ovarian cancers. Accurate diagnosis and staging facilitate optimal patient management particularly in patients desiring to preserve fertility.

Avascular necrosis of spine: a rare appearance.

Study Design. Avascular necrosis (AVN) of two contiguous vertebrae along with the intervening disc is presented. Objectives. AVN of two contiguous vertebrae and the intervening disc is a rare entity and can be confused with infective and neoplastic processes. We present the role of magnetic resonance imaging (MRI) in the diagnosis of AVN. Summary of Background Data. AVN of vertebral bodies is a known entity; however, involvement of two contiguous vertebrae along with the intervening disc is atypical. The imaging features can be confused with an infective etiology, which involves the disc more commonly as compared to AVN. Neoplastic destruction of vertebrae also needs to be ruled out in appropriate clinical situations. Methods. Frontal and lateral radiographs of the lumbar spine were performed followed by an MRI. Subsequently CT-guided fine needle aspiration cytology was performed. Results. These radiographic features were correlated with the clinical and pathologic findings. The MRI findings of a wedge-shaped lesion with classic fluid intensity (hyperintense signal, like that of cerebrospinal fluid on T2-weighted images) are characteristic of AVN. Fine needle aspiration cytology confirmed the diagnosis and excluded an infective or a neoplastic process. Conclusions. The MRI findings described in this report are very characteristic of AVN of spine. Clinical and radiologic correlation could help in making the diagnosis and avoid unnecessary investigations.

Emphysematous cholecystitis: Imaging findings in nine patients

Objective: Emphysematous cholecystitis is a severe form of acute cholecystitis and can be rapidly fatal. We present the imaging features of nine patients with proven emphysematous cholecystitis.

An unusual case of CV junction tuberculosis presenting with quadriplegia.

Study Design. Isolated tubercular involvement of craniovertebral junction in a human immunodeficiency virus–positive patient causing paraplegia and sudden death with radiologic features is presented. Objectives. Isolated involvement of craniovertebral junction by tuberculosis causing quadriparesis is a rare entity. The role of imaging features is presented in diagnosis of craniovertebral junction tuberculosis, which is a treatable disease. Early detection of this entity with prompt treatment can prevent a fatal outcome. Summary of Background Data. Tuberculosis of the cervical spine is a rare and potentially dangerous manifestation of extrapulmonary tuberculosis. The incidence is probably less than 1% of all cases of spinal tuberculosis. However, in the developing countries this constitutes an increasingly important cause of craniovertebral junction instability and cervicomedullary compression. Most of the patients present with pain in the neck and local tenderness. Neurologic deficits of varying degrees have been reported in 24–40% of cases of craniovertebral junction tuberculosis. Quadriplegia followed by sudden death is exceptional (as seen in our case). The incidence of craniovertebral junction tuberculosis in immunocompromised patients is not known. Dramatic recovery is possible if craniovertebral junction tuberculosis is detected early in its course. Prompt medical and surgical treatment may avert a potential catastrophic event in such cases. Imaging methods such as computed tomography and magnetic resonance imaging are diagnostic of this condition and aid in the detection and prompt treatment of the same. Method. Frontal radiograph of the cervical spine and chest, and lateral view of cervical spine followed by plain and contrast enhanced computed tomography scan of the cervical spine was performed to detect the lesion. Result. These radiographic features were correlated with the clinical findings. The computed tomography findings of bone destruction, prevertebral and extradural peripherally enhancing soft tissue and infiltrating opacities in the lung apexes were consistent with tuberculosis. Conclusions. The computed tomography findings described in this report are very specific for tuberculosis of the craniovertebral junction. Clinical and radiologic correlation could help in making the early diagnosis and prompt treatment possible.

Miscellaneous tumour-like lesions of the ovary: cross-sectional imaging review

Miscellaneous tumour-like ovarian lesions are histobiologically diverse, and are often mistaken for the more common ovarian cancers, leading to aggressive management. Knowledge of characteristic clinical, laboratory and imaging findings of these select non-neoplastic ovarian entities allows correct diagnoses and permits optimal management.

Benign non-cystic scrotal tumors and pseudotumors

There is a wide spectrum of benign, non-cystic scrotal lesions that show characteristic histo-morphology and natural history. While sonography is the preferred modality for the diagnosis of both testicular and extratesticular masses, MRI is used as a problem-solving modality when sonographic findings are inconclusive. This article reviews the cross-sectional imaging features of benign, non-cystic, intra- and extratesticular lesions. Definitive diagnosis of benign scrotal lesions may lead to conservative management including testicular preserving surgery.

Spectrum of medication-induced complications in the abdomen: Role of cross-sectional imaging

OBJECTIVE This article provides a comprehensive review of the role of MDCT and MRI in the diagnosis of drug-induced complications in the abdomen and pelvis in adults. A systematic organ-based review of these complications is presented, including but not limited to hepatic changes after chemotherapy, renal complications such as tumor lysis syndrome and lithium nephropathy, gastrointestinal manifestations, various opportunistic infections and secondary neoplasms, mycotic aortic aneurysm from intravesical bacille Calmette-Guérin, complications of anticoagulant therapy, and oral contraceptives. CONCLUSION Advancements in imaging have led to recognition of radiologic features of previously unsuspected diseases. Occasionally, imaging may also identify effects of treatments instituted for these diseases. Consequently, imaging plays a critical role in the accurate diagnosis of a broad spectrum of drug-induced complications in the abdomen, both in emergent and nonemergent settings. Knowledge of the natural history, clinical manifestations, and salient imaging features of these entities is crucial to facilitate accurate clinical diagnosis in a timely fashion.

Imaging of Tuberculosis of the Abdominal Viscera: Beyond the Intestines

There is an increasing incidence of both intra- and extra-thoracic manifestations of tuberculosis, in part due to the AIDS epidemic. Isolated tubercular involvement of the solid abdominal viscera is relatively unusual. Cross-sectional imaging with ultrasound, multidetector computed tomography (CT), and magnetic resonance imaging (MRI) plays an important role in the diagnosis and post treatment follow-up of tuberculosis. Specific imaging features of tuberculosis are frequently related to caseous necrosis, which is the hallmark of this disease. However, depending on the type of solid organ involvement, tubercular lesions can mimic a variety of neoplastic and nonneoplastic conditions. Often, cross-sectional imaging alone is insufficient in reaching a conclusive diagnosis, and image-guided tissue sampling is needed. In this article, we review the pathology and cross-sectional imaging features of tubercular involvement of solid abdominopelvic organs with a special emphasis on appropriate differential diagnoses.