PMC5247277_01
Microscopically, the right lung nodule consists of tumor cells demonstrating a mixture of meningotheliomatous and fibrous elements (hematoxylin and eosin stain). Note the spindle-shaped cells had ovoid or elongated nuclei and were arranged in palisades intermingled with numerous whorled nests.
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Cancer Research, for a percutaneous biopsy of a new asymptomatic nodule that appeared in a chest CT scan in the right lower lung field, histologically a benign PPM, that showed the same morphologic features as those of the previously reported lesions: transitional meningioma Grade I by the WHO grading system in 2007 (Fig. 1). Immunohistochemical examination demonstrated consistent expression of the epithelial membrane antigen and vimentin in tumor cells. Conversely, results of analyses for the S-100 protein, AE1/AE3, CAM 5.2, muscle-specific actin (HHF-35), smooth muscle actin, synaptophysin, neuron-specific antigen, and desmin were all negative.
Chest CT scan showing a well-demarcated nodule in the right lower lung field. The nodule has grown very slowly (left, an 18-mm nodule in 2007; right a 27.5-mm nodule in 2015).
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Although the right lung nodule has grown, the growth is very slow, with a doubling time of 1393 days, the patient is otherwise asymptomatic (Fig. 2).
Chest CT scan showing a 6-mm nodule in the left upper lung field.
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Subsequent to the previous report in 2010, new lesions appeared in the bilateral lung fields with quite a slow growth rate (Fig. 3).