PMC6010608_01
a. Nodule in the right upper lobe centered around the bronchus (solid blue arrow) on September 2016 slowly growing since December 2008 (red arrow). b. Axial CT image slightly inferiorly shows the slowly enlarging nodule on September 2016 (solid blue arrow) as compared with December 2008 (red arrow). c. Coronal multiplanar reconstruction CT image shows the slowly enlarging nodule on September 2016 (solid blue arrow) as compared with December 2008 (red arrow). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
gr1.jpg
PMC6010608_01_gr1.jpg
fig1
In the right upper lobe, this abnormality was possibly associated with an endobronchial lesion (Fig. 1a), although this was not well appreciated at the time of initial evaluation and this was only recognized on subsequent review many years later when she presented again. On our imaging assessment in 2016, a CT scan without contrast demonstrated a dominant slowly growing 14 mm nodule apparently centered along a subsegmental branch of the right apical segmental bronchus (Fig. 1b), in the same area where linear fibrosis was noted in 2008. Multiple prominent mediastinal lymph nodes were also noted as well as multiple indeterminate nodules along the fissures (Fig. 1c).
Representative photomicrographs of the endobronchial tumor. At low magnification (12.5x, upper left; H&E), a polypoid submucosal proliferation projects into the lumen of a small bronchus. At medium magnification (100x, upper right; H&E), small glandular structures, cords, and spindle cells are present in a background of variably fibrotic and myxoid stroma. Two distinctive components are present, with an epithelioid ductal cell component surrounded by a clear to spindled myoepithelial component with focal overgrowth of the latter, more easily seen with immunohistochemistry (all at 100x, bottom row) that shows immunoreactivity of the ductal cell component for pancytokeratin AE1/AE3 (brown cytoplasmic pigment indicates positive reaction) and staining of the surrounding myoepithelial cell component and nearby spindle cells for smooth muscle actin (SMA, brown cytoplasmic) and S-100 protein (red cytoplasmic and nuclear). Both components display immunoreactivity for TTF-1 (brown nuclear). These features are characteristic of pneumocytic adenomyoepithelioma. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
gr2.jpg
PMC6010608_01_gr2.jpg
fig2
Histopathologic evaluation of the lobectomy specimen demonstrated a polypoid and well-circumscribed submucosal proliferation of neoplastic cells projecting into the lumen of a small bronchus (Fig. 2).