Mucoepidermoid Carcinoma of the Lung with Intracranial Metastases: Pathologic Findings

15 Feb
2015

Pathologic Findings
Gross inspection: Bilateral bullous pulmonary emphysema, particularly of the right upper lobe, was noted. Cross sections through the right upper lobe bronchus revealed mild thickening and narrowing of its first bifurcation. The mucosa overlying this stenotic portion was normal except for congestion and focal granularity The submucosa was expanded. Adjacent lobar lymph nodes and the interlobar, aorto-pulmonic and hilar lymph nodes were extensively involved with metastatic tumor (Fig 2). The neuropathologic examination revealed two well circumscribed metastatic lesions: a right, posterior, frontal lobe mass located 1 cm from the cortical surface, and a left subcortical, white matter mass in the region of the insula. There was extensive atherosclerosis, ischemic infarction of the small bowel, and evidence for a recent myocardial infarction. canadian drug mall

Light microscopy: Sections from the stenotic right upper lobe bronchus were stained with hematoxylin and eosin. The mucosa showed a few areas of moderate dysplasia, but was otherwise normal. Examination of the right upper lobe bronchial mucous glands demonstrated hyperplasia, squamous metaplasia, and malignant transformations, both in-situ and with infiltration into the glandular epithelial cells. This was considered to be the primary tumor focus.
The tumor cells were predominantly arranged in sheets and smaller nests. The epidermoid cells were polygonal with distinct borders and abundant eosinophilic cytoplasm. The nuclei were centrally and peripherally located, hyperchromatic and vesicular, with brisk mitoses. In areas, vague glandular formations were seen. Some cells contained intracytoplasmic lumina. Mucin was positive, within the intracytoplasmic lumina and occasionally in the cytoplasm in both the primary tumor focus and the metastatic tissue foci. Bizarre tumor giant cells were noted. The lymph node (Fig 3 and 4) and intracranial metastases had identical histologic characteristics.

Figure 2. Gross pathologic inspection demonstrates mild bronchial wall thickening due to tumor involvement of the first bifurcation of the right upper lobe bronchus (large arrow). Also noted is the dense involvement of the peribronchial lymph nodes with tumor metas-tases (small arrows).

Figure 2. Gross pathologic inspection demonstrates mild bronchial wall thickening due to tumor involvement of the first bifurcation of the right upper lobe bronchus (large arrow). Also noted is the dense involvement of the peribronchial lymph nodes with tumor metas-tases (small arrows).

Figure 3. Light microscopy of lymph node metastases illustrates the epidermoid characteristics of the tumor.

Figure 3. Light microscopy of lymph node metastases illustrates the epidermoid characteristics of the tumor.

Figure 4. Mucus production in a lymph node metastasis is demonstrated by positive mucicarmine staining.

Figure 4. Mucus production in a lymph node metastasis is demonstrated by positive mucicarmine staining.

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