Mediastinal nodal angiomatosis - an unusual mass lesion in the superior mediastinum

Full text: A 54-year-old male, lifelong non-smoker, presented to the authors' hospital with a 5-day history of fever and productive cough, not improving on oral amoxicillin. His past medical history was unremarkable. On examina tion, he was febrile, tachycardic and tachypneic, and had right basal crackles on auscultation. Initial blood tests revealed a leucocytosis with increased neutrophils and normal lymphocytes. C-reactive protein was elevated at 312 mg/L 5). The coagulation profile was unremarkable. The initial chest X-ray (CXR) showed areas of opacifi cation in the right lower lobe and a right paratracheal mediastinal bulging (Fig, 1). A previous CXR from 6 years before, unrelated to this recent presentation, was normal. Further evaluation by contrast-enhanced chest CT (SIEMENS Sensation 16 (Siemens, Erlangen, Germany); slice thickness 3 mm) showed a well-defined heteroge neous 4.0 x 4.8 cm mass lesion in the superior mediast num with densities of 60-70 HU, separate from vessels, the esophagus or the trachea (Fig. 2a) along with bilateral lower lobe patchy confluent pulmonary infiltrates (not shown), more conspicuous on the right. The patient's hospital stay was complicated by a non-ST elevation myocardial infarction, which precluded him from having a transbronchial biopsy of the mediastinal mass. The patient's serum tested positive for mycoplasma pneumo niae antibodies with a titre of 640 40); the pneumonia was successfully treated with a course of oral doxycycline administered over 14 days, the symptoms fully resolving. He was eventually discharged, having recovered from the pneumonia and from the myocardial infarction. A subs quent CT scan performed 3 months later showed persis tence of the mediastinal mass with no significant changes in size or density (Fig. 2b); the bilateral pneumonic infil trates have fully resolved. The ensuing endobronchial ultrasound (EBUS)-guided needle aspiration with biopsy of the mediastinal mass produced a sample of macrophages and erythrocytes, but no malignant cells. Still without a clear diagnosis, MRI (SIEMENS Avanto, 1.5 T, MAGNEVIST contrast, 10 mL) was performed. The mass appeared as a hyper intense lesion on T2 weighted imaging (Fig. 3a) and as a solid well-defined heterogenous enhancing tumour with prolonged pooling of contrast material on dynamic T1 acquisition (Fig, 3b-e). Finally, the lesion was thoracoscopically excised, given the presence of an almost 5-cm mediastinal mass with vascular supply. Histology showed florid.