Spontaneous Regression of Metastatic Lung Adenocarcinoma Following a Core Biopsy.

of PPM was reported in 1982 and since then about 60 cases have been reported in the English literature.3,4 The histologic origin of PPM is unclear. It is hypothesized that they either arise from ectopic arachnoid cells, the small meningeal epithelial nodules or subpleural pluripotent cells.5 The disease generally affects patients in fourth to seventh decade of life and is more common in females. Most cases are asymptomatic at presentation, with lesions being found incidentally on chest imaging. In symptomatic cases, chest pain, cough, hemoptysis, and breathlessness are the common presenting features.4 PPM usually presents as a single, peripheral, round or lobulated, noncalcified parenchymal nodule with well circumscribed margins. Few cases of multiple lung nodules mimicking metastatic lung disease have been reported.6 In most cases the bronchi or pleura are not involved. Endobronchial presentation of meningioma is uncommon, and to the best of our knowledge, only one case of endobronchial PPM has been previously reported.7 Our patient had a single large lobulated endobronchial mass which was well circumscribed and appeared to arise from the right upper lobe bronchus. Most cases of PPM are benign, slow growing tumors which have an excellent prognosis with very few cases of metastases or recurrence. Only 3 cases of malignant transformation of PPM have been reported thus far.8 Microscopically, these tumors are composed of spindle-shaped or ovoid cells arranged in lobules or a whorl pattern with psammoma bodies commonly being seen. In our case histopathological examination showed sheets and papillae of uniform cuboidal cells with round nuclei with mild nuclear atypia. Immunohistochemistry staining was positive for vimentin and EMA, characteristic of meningioma. The treatment of choice for pulmonary meningioma has historically been surgical resection. While wedge resection is ideal for benign peripheral lesions, lobectomy is preferred for malignant or central lesions. In view of the benign nature of the disease and low recurrence, we attempted to do a minimally invasive, endobronchial resection. Complete patency of bronchial tree was achieved with complete reexpansion of the collapsed lung postendobronchial resection. To the best of our knowledge this is the first case of endobronchial PPM where bronchoscopic resection was attempted. However, the patient eventually required thoracoscopic bilobectomy as there was a recurrence after 3 months. In conclusion, PPM is a rare disease with endobronchial presentation being reported only 1 case earlier. It should be considered in the differential diagnosis of endobronchial mass lesions and peripheral lung nodules.