Department of Pathology, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
Am J Surg Pathol. 2013 Feb;37(2):155-66. doi: 10.1097/PAS.0b013e31826a92f5.
Solitary fibrous tumor (SFT) is a ubiquitous neoplasm that arises most commonly from the pleura. SFT arising within lung parenchyma (intrapulmonary SFT) has been rarely reported and is therefore not well recognized. We present a clinicopathologic and immunohistochemical study of 24 cases of primary intrapulmonary SFT. Patients' ages ranged from 44 to 83 years (mean, 58 y). None of the patients had evidence or history of a similar tumor elsewhere. Tumor size ranged from 2.3 to 22 cm (mean, 8.5 cm). On the basis of the degree of cytologic atypia, cellularity, mitotic activity, and areas of necrosis, the lesions were divided into low-grade, intermediate-grade, and high-grade histology. Twenty-one tumors showed the conventional features of SFT of low-grade histology (<5 mitoses per 10 high-power fields), with alternating bands of rope-like collagen flanked by a bland-appearing spindle cell proliferation. Hemangiopericytic, angiofibromatous, and a neural-like plexiform growth pattern were also observed. Five of 21 cases showed an "adenofibromatous" appearance imparted by entrapped normal airspaces at the advancing edges of the lesion. One intermediate-grade tumor showed overall increased cellularity with plump, pleomorphic nuclei, 5 to 10 mitoses per 10 high-power fields, and focal areas of classic SFT. Two cases showed high-grade features at initial presentation, with areas resembling a pleomorphic high-grade sarcoma admixed with foci of conventional, low-grade SFT. Immunohistochemical staining analyses performed in 13 cases showed positivity of the tumor cells for CD34, bcl-2, and CD99 in the majority of cases tested. Clinical follow-up was available in 18 patients, with long-term follow-up (>5 y) in 6. Fourteen (14/18) patients were alive and well without evidence of disease 1 month to 14 years after initial diagnosis. Three patients died of their tumors after 4, 5, and 7 years; in 2 of them the initial tumor was of low-grade histology, but the recurrence/metastases showed a high-grade histology; the third fatal case showed a tumor with high-grade histology at initial diagnosis. One patient with intermediate-grade histology also had chest wall metastases at 5 years but was subsequently lost to follow-up. The results of our study indicate that although tumors with overtly malignant histologic features can be expected to behave as high-grade sarcomas, tumors with bland-appearing morphologic features at presentation may also follow an aggressive behavior. Adequate excision with close clinical follow-up, thus, appears to be the most prudent course of action for the management of primary intrapulmonary fibrous tumors.
孤立性纤维瘤（SFT）是一种普遍存在的肿瘤，最常见于胸膜。发生于肺实质内的 SFT（肺内 SFT）很少见，因此认识不足。我们报告了 24 例原发性肺内 SFT 的临床病理和免疫组织化学研究。患者年龄 44 至 83 岁（平均 58 岁）。无患者有其他部位类似肿瘤的证据或病史。肿瘤大小为 2.3 至 22cm（平均 8.5cm）。根据细胞异型性、细胞密度、有丝分裂活性和坏死区的程度，病变分为低级别、中级别和高级别组织学。21 例肿瘤表现为低级别 SFT 的常规特征（每 10 个高倍视野＜5 个有丝分裂），交替出现绳状胶原带，周围为外观温和的梭形细胞增生。也观察到血管外皮细胞瘤、血管纤维瘤样和神经样丛状生长模式。21 例中有 5 例显示出“腺纤维瘤样”外观，病变边缘有正常空气腔被包裹。1 例中级别肿瘤表现为整体细胞密度增加，核肥大、多形性，每 10 个高倍视野有 5 至 10 个有丝分裂，并有典型 SFT 的局灶区。2 例在初次就诊时表现为高级别特征，有类似于多形性高级别肉瘤的区域，混杂有局灶性、低级别 SFT。在 13 例中进行了免疫组织化学染色分析，大多数病例的肿瘤细胞 CD34、bcl-2 和 CD99 阳性。18 例患者可获得临床随访，6 例患者获得长期随访（＞5 年）。初次诊断后 1 个月至 14 年内，14 例（14/18）患者存活且无疾病证据。3 例患者在 4、5 和 7 年后死于肿瘤，其中 2 例初始肿瘤为低级别组织学，但复发/转移显示高级别组织学；第 3 例致命病例的初始诊断为高级别组织学肿瘤。1 例中级别组织学患者在 5 年内也有胸壁转移，但随后失访。我们的研究结果表明，虽然具有明显恶性组织学特征的肿瘤预计表现为高级别肉瘤，但表现出形态学特征温和的肿瘤也可能表现出侵袭性行为。因此，充分切除并密切临床随访似乎是管理原发性肺内纤维瘤的最谨慎方法。
