Can pulmonary sclerosing haemangioma be accurately diagnosed by intra-operative frozen section?

Pulmonary sclerosing haemangioma is a rare benign tumour with a characteristic variegated histological pattern. In this retrospective study we aimed to identify features that can aid in making a correct diagnosis and avoiding potential pitfalls at the time of intra-operative frozen section.

Twenty cases of pulmonary sclerosing haemangioma with intra-operative frozen section were reviewed. The four major histological patterns (solid, sclerotic, papillary and haemorrhagic) were found in various combinations in the frozen sections. In 17 cases, three or more patterns were present. There could be focal areas mimicking epithelioid haemangioendothelioma or carcinoid tumour. Intra-operative imprint/scrape cytology served as a helpful adjunct in confirming the cytological blandness, although occasional atypical cells could be present. An intra-operative frozen section diagnosis of 'sclerosing haemangioma' or 'benign tumour' was given in 14 cases; the diagnosis was deferred in six cases. Retrospective analysis of the deferred cases showed that a definitive intra-operative diagnosis could have been made in three, because three or more major histological patterns were present. One case showed a pure papillary pattern at frozen section, mimicking the appearance of papillary adenocarcinoma (primary or secondary), bronchioloalveolar carcinoma, epithelioid mesothelioma or papillary adenoma; two tumours from a patient with multicentric disease showed widespread significant cytological atypia in the tumours raising a serious consideration of malignancy.

A diagnosis of pulmonary sclerosing haemangioma can be made at intra-operative frozen sections in most cases based on the tumour circumscription and variegated histological patterns. When only a single histological pattern is identified or when there is significant cytological atypia, distinction from other tumours can be problematic, and the diagnosis is best deferred.