Hemangioblastoma-like Clear Cell Stromal Tumor of the Lung

Abstract

The authors report 2 cases of an apparently unpublished stromal tumor of the lung characterized by a predominantly endobronchial growth pattern and benign-appearing clear cells. Both tumors were discovered incidentally in adult patients during routine workups for other medical reasons and treated with lobectomy. On gross inspection there was no evidence of infiltration of the adjacent lung tissue. Microscopically, both lesions featured monotonous oval-shaped to spindle-shaped cells growing in a vaguely nested pattern. The cytoplasm was slightly vacuolated or granular. In 1 case there was a variable admixture with mature fat. Immunohistochemistry was negative for markers of epithelial and stromal differentiation except for vimentin. A focal reaction for CD34 was seen in 1 case. No mutation of coding sequence of VHL gene was seen in one case. Medical follow-up at 1 year was negative for tumor recurrence or metastases. The broad differential diagnosis within the spectrum of stromal lung tumor is discussed. Owing to distinctive microscopic features such as the nesting of clear cells within a vascularized background, both tumors appeared similar to hemangioblastoma, although the expected immunohistochemical profile of the latter was not fully expressed. Because of pattern of growth seen in both lesions we believe that the appellation of endobronchial, hemangioblastoma-like clear cell stromal tumor may be provisionally designed.

YAP1–TFE3 gene fusion variant in clear cell stromal tumour of lung: report of two cases in support of a distinct entity

“…All but two of the reported cases showed minimal cytological atypia, no nuclear pleomorphism and no mitotic activity. 1,2,12 The two pulmonary cases reported in the current study showed similar morphological features, although clear cells appeared to be only a minor component in our cases. Specifically, in case 2, we were unable to find any areas that shows definitive cytoplasmic clearing.…”

“…These tumours were characterised by a hypervascularised stroma and dilated blood vessels, hence the original name ‘haemangioblastoma‐like clear cell stromal tumour of the lung’. All but two of the reported cases showed minimal cytological atypia, no nuclear pleomorphism and no mitotic activity 1,2,12 . The two pulmonary cases reported in the current study showed similar morphological features, although clear cells appeared to be only a minor component in our cases.…”

“…In 2013, Falconieri et al described two endobronchial tumours under the name 'haemangioblastoma-like clear cell tumour of lung': a neoplasm of unknown histogenesis that was thought to be distinct from clear cell 'sugar' tumour. 1 Subsequently, Lindholm and Moran described five additional cases, expanding on the clinicopathological features of the original report. 2 Until recently, YAP1-TFE3 gene fusions were only described in epithelioid haemangioendothelioma (EHE) [3][4][5][6][7][8][9][10][11] ; however, Agaimy et al have now described novel recurrent YAP1-TFE3 gene fusions in these clear cell (haemangioblastoma-like) stromal tumours of the lung.…”

Case Report: Hemangioblastoma- Like Clear Cell Stromal Tumor of the Left Lower Lung

“…However, they may be rarely found in the retroperitoneum, pelvic cavity, presacral region, kidney, maxillary sinus, and adrenal gland ( 4 ). In 2013, Falconieri et al ( 5 ) reported the first two cases of pulmonary clear cell stromal tumors with previously unreported histological features similar to hemangioblastoma, which they named “hemangioblastoma-like clear cell stromal tumor of the lung”. The HLCCST is very uncommon, to the best of the authors’ knowledge, only 13 cases have been reported in four articles.…”

EWSR1‐CREM fusion in pulmonary mesenchymal neoplasm showing distinctive clear cell morphology

“…8 Overall, the present histological and immunoprofiling features do not support the diagnosis of hyalinizing CCC. Hemangioblastoma-like clear cell tumor (HLCCST) of the lung, recently designated by two independent publications, 12,13 is also one of the differential diagnoses. Although rich and fine capillary networks typically shown in HLCCST of the lung are not found in the present case, further molecular testing of the previously reported cases 12,13 are required.…”