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Pulmonary Malignant Fibrous Histiocytoma

Localized Fibrous Tumour of the Pleura

Extrapleural solitary fibrous tumour

Hemangiopericytoma (Lipomatous Hemangiopericytoma)

Fibroblastic/Myofibroblastic tumours

Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm of ubiquitous location. In addition to its classic presentation as a pleural-based mass, it can be encountered in a variety of other sites. A pleural-based lung lesion can be easily accessed by radiologic guidance for cytologic study. Several reports have described the cytologic findings of SFT at various locations, including the lung. However, diagnostic difficulties can occur due to unusual clinical, radiologic, atypical cytomorphologic, and histologic features. We describe a case of intrapulmonary SFT in which a false-positive malignant diagnosis was rendered on fine-needle aspiration biopsy and concurrent surgical core biopsy prior to radiofrequency ablation. The patient died of procedural complications, and an autopsy was performed. Retrospective study of the case, especially correlation of cytologic, histologic, autopsy findings, and immunohistochemistry results were helpful in correctly diagnosing the case as SFT. We are reporting this case with emphasis on avoiding diagnostic pitfalls by being familiar with the accepted cytohistologic features and appropriate immunohistochemical results.

Intrapulmonary solitary fibrous tumor in an eight-year-old male.
Pediatr Pulmonol. 2005 Sep;40(3):261-4.

We describe an 8-year-old male who had an intrapulmonary solitary fibrous tumor (SFT). SFTs of the pleura are now thought to originate from subpleural mesenchymal cells, and a pathological diagnosis is obtained by a specific marker, i.e., CD34 expression on the tumor cells. The SFT reported here is an extremely rare phenotype in two respects: it originated in a child under age 10 years, and it expanded in an intrapulmonary fashion.

Primary pulmonary haemangiopericytoma: a very rare case.
Heart Lung Circ. 2005 Dec;14(4):263-5. Epub 2005 Jun 1.

Hemangiopericytoma is a mesenchymal neoplasm originating from pericytes--a cell type that surround capillaries. Its primary localization in the lung is extremely rare. A 41-year-old male patient was admitted to our hospital with an abnormal opacity on his chest X-ray. A primary tumor, located in the left upper lobe, was resected, and final diagnosis was hemangiopericytoma of pulmonary origin. The patient has been well for 2 years since the operation with no sign of recurrence or metastasis. A rare case of primary pulmonary tumor has been presented, and possibilities and difficulties in diagnosis as well as therapy are discussed.

Primary lung hemangiopericytoma--a rare neoplasm with a long course of recurrence over many years.Pneumonol Alergol Pol. 2001;69(5-6):290-4

Hemangiopericytoma (HPC) is a rare neoplasm arising from pericytes that occur mostly around smaller vessels. Up to now only about 100 cases have been reported to arise primarily in the lung. The behavior of pulmonary hemangiopericytomas is difficult to predict and all tumors should be considered potentially malignant, even though the criteria for malignancy are not well developed. The diagnosis of HPC is known to confound even experienced pathologist. Pericytes lack readily identifiable morphologic features, therefore hemangiopericytomas are often confused with other soft tissue tumors that may have hemangiopericytoma--like pattern. We report a rare case of primary HPC of the lung with an asymptomatic, long course of the disease. The diagnosis of hamartoma was established after the first operation. Subsequently, seven years later, a chest radiograph revealed new lesions. Histological examination, including immunohistochemistry lead to the final diagnosis of hemangiopericytoma. The small number of cases of primary pulmonary hemangiopericytoma makes it difficult to define the correct histopathological diagnosis especially without modern methods.

Report of an intrapulmonary solitary fibrous tumor: fine-needle aspiration cytologic findings, clinicopathological, and immunohistochemical features.Diagn Cytopathol. 1996 Feb;14(1):64-7

The authors describe a rare case of intrapulmonary solitary fibrous tumor (SFT). Morphologically, the tumor showed a disorganized or "patternless" arrangement of plump to spindle cells in a collagenous stroma. Tumor cells were immunoreactive for vimentin, but not for keratin, carcinoembryonic antigen, epithelial membrane antigen, factor-VIII related antigen, S-100 protein, desmin, and actin. These immunohistochemical findings suggested fibroblastic differentiation, in keeping with the putative submesothelial origin of the tumor. The problems concerning the fine-needle aspiration (FNA) preoperative diagnosis of SFT are briefly discussed.

Primary hemangiopericytoma of the lung.Zhonghua Zhong Liu Za Zhi. 1993 Mar;15(2):149-51

Primary pulmonary hemangiopericytoma is a rare form of soft tissue sarcomas. Only six cases were reported in the Chinese literature. Three additional cases treated surgically are now presented, bringing the total to nine and their pathologic and clinical aspects are briefly reviewed. The tumor derives from pericytes and should not be confused with hemangioendothelioma. Most of the patients were asymptomatic and the lesion was detected on routine chest roentgenography. The nine patients had chest pain, fever, cough, dyspnea, hemoptysis or other symptoms, but the symptoms do not differ from those of other lung tumors. Some radiologic features can arouse suspicion of hemangiopericytoma. MRI has a distinct advantage over CT in the tumor imaging. The microscopic morphology is characterized by multiple proliferating capillaries with normal endothelial cells surrounded by proliferating pericytes. For primary pulmonary hemangiopericytoma, the only effective treatment is adequate resection varying from a wedge resection to a pneumonectomy depending on the location and extent of the tumor.