The value of magnetic resonance imaging (MRI) in the evaluation of vascular abnormalities in the chest is well established.

The value of magnetic resonance imaging (MRI) in the evaluation of vascular abnormalities in the chest is well established. To our knowledge, however, MRI in Castleman's disease of the chest had not been reported previously. We current a case of Castleman's disease of hyaline vascular token involving the pulmonary hilum where MRI was equal to comput tomography in showing the size of the disease, but was more informative in demonstrating its relationship with vascular structures

Castleman's disease or giant lymph node hyperplasia is a rare, benign disorder of unknown etiology involving lymph nodes at various sites, predominantly in the mediastinum.[1] sum of two units histologic variants, hyaline vascular (HV) and plasma lonely dwelling types have been described.[2] Since HV emblem is extremely hypervascular, it appears as a densely enhancing lesion forward contrast-enhanced computed tomography (CT) and in parahilar regions may not be distinguishable from major vessels[3]

Magnetic resonance imaging (MRI) has been used in evaluation of cardiovascular abnormalities.[4] We report a typical case of Castleman's disease in which MRI was helpful in defining the nature and reach of the disease.

CASE REPORT

A 45-year-old nonsmoking woman was referr from an outside hospital with the diagnosis of right parahilar mass that was discovered upon routine chest radiographs and confirmed forward non-contrast CT scan. She initially readyed with 2 years' history of nonproductive cough and retrosternal chest pain. The pain has increased in intensity and was not associated with any other cardiac symptoms. A chest radiograph about a year ago had been reported as apparently abnormal and at that time, the patient refused further investigations. Findings from physical examination were unremarkable and originates of laboratory investigations and electrocardiogram were normal.

Chest radiograph revealed a right hilar mass. Contrast-enhanced CT showed an enhancing lesion in the right parahilar area that was compressing the right main-stem bronchus and could not be separated from main pulmonary tubes (Fig 1). Transaxial MRIs showed this mass to be hypointense compared with mediastinal fat upon [T.sub.1]-weighted images (TR/TE 633/20) and hyperintense forward [T.sub.2]-weighted images (TR/TE 2000/100) (Fig 2 right). The mass reach forthed between the right pulmonary artery and the right main-stem bronchus. The mediastinal lymph nodes also appeared hyperintense onward [T.sub.2]-weighted images.

Abdominal and pelvic CT was normal. No endobronchial disease was noted forward bronchoscopic examination and transbronchial biopsy specimens were not diagnostic. A percutaneous transthoracic fine-needle aspiration biopsy specimen showed large atypical cells; however, Hodgkin's disease could not be rul gone out Because lymphoma was considered a likely diagnosis, right thoracotomy was performed. A fine spongy mass measuring 3 x 4 cm in diameter was erect located in between right main-stem bronchus and right pulmonary artery with enlarged hilar lymph nodes. Frozen section exclud malignancy and lymphoma.

Microscopically the lung mass and hilar lymph nodes showed features of Castleman's disease, HV emblem The patient received no treatment and remained well after 1-year follow-up Further CT of the chest revealed no change in right parahilar mass.

DISCUSSION

Castleman and colleagues[1] first described this entity in 1956 while reviewing the cases of tumors of the thymus. Subsequently brace distinct histologic types that differ in their clinical implications were recognized.[2] The more customary HV type, which accounts for 80 to 90 percent of all cases, is usually asymptomatic or the patient may complain of cough or sensation of hurry due to tracheobronchial compression. In greatest in number cases (60 percent), the disease is seen in the thorax; however, it can happen in any other sites in which lymph nodes are normally raise In order of commonness the intrathoracic sites involved include anterior mediastinum, the hila of lung and posterior mediastinum. Histologically, HV model contains small lymphoid follicles characterized by means of radially penetrating capillaries and concentric layering of surrounding lymphocyte The interfollicular belts are well vascularized and contain varying numbers of small lymphocyte scattered plasma small rooms and occasional immunoblasts and suppressor T enclosed spaces Surgery may be curative. In les public plasma-cell type, extrathoracic sites are commonly involved and the patient may have excitement anemia, hypergammaglobulinemia, nephrotic syndrome, or peripheral neuropathy. Histologically, it has larger follicles with intervening sheets of plasma small cavitys and is less vascular. Transition between sum of two units types has been described.

The radiographic findings of Castleman's disease are usually nonspecific. The lesions have been described as well orbiculared lobulated soft-tissue masses.[5] The intrathoracic lesions have a disposition to lie on one side of midline or overlie the hilum. Unlike curvilinear calcification of cystic mediastinal lesions, the calcification in Castleman's disease is usually punctate and discrete.[6] As demonstrated in our patient, the dynamic CT scan displays densely enhancing soft-tissue lesion, especially in HV type[3] The masses in Castleman's disease are self-same vascular and stain with a compact homogenous blush in the capillary phase of arteriography. Preoperative embolization of the feeding ducts which may arise from bronchial arteries in the thorax or from lumbar arteries in the peritoneum, has been used to resolve into the intraoperative hemorrhage.[7]

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