Solitary Pulmonary Capillary Hemangioma: Recognition, Clinicopathological Characteristics, and Recent Advances.

Solitary pulmonary capillary hemangioma (SPCH) is a rare, benign nodular lesion composed of proliferating capillaries in the lung. While pulmonary capillary hemangiomatosis-characterized by diffuse or patchy capillary proliferation in the lung leading to pulmonary hypertension and eventually fatal outcomes-has been recognized since 1978, the concept of solitary capillary hemangioma of the lung began to emerge in 2000 and has been increasingly recognized through subsequent reports. SPCH typically presents as a solitary nodule < 20 mm in diameter, often appearing as a ground-glass nodule on computed tomography. These features can closely mimic early-stage lung adenocarcinoma, posing a diagnostic challenge. In addition, SPCH is often difficult to palpate during surgery, which occasionally complicates intraoperative management. This review outlines the historical background of SPCH and summarizes its clinicoradiological, surgical (including intraoperative diagnosis), pathological (gross appearance and histopathological findings), and molecular characteristics. In particular, a literature review of previous studies, together with our own cases, highlights its distinguishing clinicoradiological features. Furthermore, SPCH is discussed in the broader context of pulmonary vascular tumors, and future directions for research and clinical practice are proposed.