Solitary pulmonary capillary hemangioma: Clinicopathologic and radiologic characteristics of nine surgically resected cases.

BACKGROUND

Solitary pulmonary capillary hemangioma (SPCH) is an extraordinarily rare capillary derived mesenchymal neoplasm. Although routine morphology and immunohistochemistry are adequate for the diagnosis of classical SPCH in surgical specimens, true gross appearance identification of most tumor themselves and diagnosis for some exceptional cases are still very difficult. Furthermore, preoperative imaging and frozen diagnosis remain a challenge.

METHODS

We reported nine original cases of solitary pulmonary capillary hemangioma and summarized the clinical characteristics of twenty-one reported lesions. Imaging materials were reviewed by the image experts of our hospital. Quick hematoxylin-eosin stained intraoperative frozen sections and routine histological diagnosis were re-confirmed by 3 specialist pathologists with at least 10 years of diagnostic experience in our department. Immunohistochemistry analysis was performed on formalin fixed archival tissue. The surgical methods, following up information and prognosis were retrospectively analyzed.

RESULTS

In imaging, three tumors showed solid nodules, three cases displayed mix ground glass nodules, two nodules were pure ground glass density, and one case was a cystic-solid mass. Macroscopically, solitary pulmonary capillary hemangiomas were ill-defined soft hemorrhagic lesion with pale yellow or dark brownish cut surface. Two cases had a clear boundary and seven lesions were poorly demarcated. Typical morphological features were densely proliferating thin-walled capillaries composing of single layer of flatten or cuboidal endothelial cells within the thickened alveolar septa. One case was mistaken for a histiocytogenic lesion during freezing. The cystic-solid lesion showed a hyperplasia capillary network along the submucosal interstitium of bronchioles. Immunohistochemically, tumor endothelial cells were positive for ERG, Fli-1, CD31, CD34 and Vimentin and negative for CK, α-SMA, TTF-1, HMB45, S-100 and CD68. Lobectomy was performed on seven cases, wedge resection and segmentectomy were proceeded in two patients respectively. Follow up information showed no evidence of complication or recurrence.

CONCLUSIONS

Solitary pulmonary capillary hemangioma has special imaging and various histological features and must be distinguished from small benign lung lesions and preinvasive cancer. Although the prognosis of this tumor is good after surgical resection, the correct interpretation of the gross appearance and radiographic findings are still important. Choosing appropriate resection mode depends on accurate evaluation preoperative and intraoperative.