Cytokeratin-positive malignant solitary fibrous tumour of the pleura: an unusual pitfall in the diagnosis of pleural spindle cell neoplasms

Solitary fibrous tumor occurring at unusual sites: A clinico-pathological series of 31 cases with emphasis on its wide morphological spectrum

Solitary fibrous tumor (SFT) is a relatively rare mesenchymal fibroblastic tumor occurring most commonly in adults with no gender predilection. Although the pathological diagnosis of SFT is usually straightforward, some difficulties may occasionally arise mainly due to the wide morphological spectrum exhibited by this tumor. In the present paper we aimed to evaluate the unusual clinicopathological features in a series of 31 SFTs arising from parenchymal organs, superficial soft tissues and deep soft tissues. Our results emphasize that SFTs may occur anywhere, including unusual sites such as periosteum of the thoracic spine, mesorectal tissue, hepatic hilum, paravescial space, kidney and breast. Moreover, a wide morphological spectrum was observed in tumors included in our series. The most striking morphological features observed included: extensive lipomatous component, myxoid stromal changes, epithelioid cell component, metaplastic mature bone, neurofibroma-like, myxofibrosarcoma-like and pseudoalveolar-like areas. Additionally, multinucleated giant cells and sarcomatous dedifferentiation were also identified. Our paper emphasizes that SFT may occur in unusual anatomical locations and exhibits a wide morphological spectrum. Pathologists must be aware of these features to avoid confusion with other benign and malignant neoplasms that may show overlapping morphological features.

Malignant solitary fibrous tumor of the pancreas: a case report

Background

Solitary fibrous tumors (SFTs) are rare tumors, mostly derived from connective tissue mesenchymal cells that arise from the pleura. There are very few reports of primary pancreatic SFT. Preoperative diagnosis is difficult owing to the lack of distinctive radiological findings. We report a case of pancreatic SFT with particularly rare malignant findings.

Case presentation

A 60-year-old man was referred to the hospital because of a right upper quadrant mass and abnormal liver function test results. Contrast-enhanced computed tomography (CT) showed a well-defined enhanced tumor measuring approximately 8 cm in the pancreatic head. Magnetic resonance imaging (MRI) showed T1WI hypointensity, T2WI hyperintensity, and DWI hyperintensity. The main pancreatic duct and common bile duct were dilated owing to obstruction by the tumor. The following tumor markers were mildly elevated: carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), SPan-1, and DUPAN-2. The histological diagnosis obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) was negative for pancreatic ductal carcinoma, malignant lymphoma and neuroendocrine tumor, suggesting the possibility of mesenchymal tumor, but the diagnosis was not confirmed. The patient was judged suitable for surgery and underwent subtotal stomach-preserving pancreatoduodenectomy with D2 lymph node dissection. On histopathological examination of the resected specimen, infiltrating spindle-shaped cells had proliferated, containing numerous mitotic figures, with necrotic findings inside the tumor. Immunostaining was positive for cluster of differentiation-34 (CD34), B cell CLL/lymphoma-2 (Bcl-2), and signal transducer and activator of transcription (STAT6). On the basis of these findings, a diagnosis of malignant pancreatic SFT was made. The patient remains free of recurrent disease after 12 months of follow-up without adjuvant therapy and he is being carefully followed up as an outpatient.

Conclusions

We experienced a case of malignant pancreatic head SFT. Immunohistochemical staining of the extracted specimens was useful for diagnosis.

The Diagnosis of Pleural Tumors Other Than Mesothelioma

CONTEXT

- Pleural pathology has been dominated by discussions relating to the diagnosis, prognosis, etiology, and management of malignant mesothelioma. However, there exists a diverse group of other neoplasms that involve the pleura; the most common by far is metastatic carcinoma, usually of pulmonary origin. Other metastatic tumors of varied histogenesis do occur but are less common. Primary pleural neoplasms other than diffuse malignant mesothelioma are either uncommon or rare and have received less attention.

OBJECTIVE

- To provide a review of those diverse tumors that can involve the pleura other than mesothelioma in order to facilitate their accurate diagnosis.

DATA SOURCES

- Review of relevant literature published via PubMed and other search engines.

CONCLUSIONS

- A wide variety of tumors can involve the pleura. In most cases, the approach of considering the morphologic features with appropriate immunohistochemistry, in the correct clinical context, allows for a confident diagnosis. For a number of those soft tissue tumors that are well recognized in the pleura, such as solitary fibrous tumor, desmoid-type fibromatosis, synovial sarcoma, and epithelioid hemangioendothelioma, novel markers now exist based on an understanding of the individual tumors' molecular characteristics. Primary pleural lymphomas are rare with poor prognosis. They represent localized specific diffuse large B-cell lymphomas, with either post-germinal center B-cell or plasma cell lineage, arising in the context of either immunodeficiency or immune sequestration and with viral infection.

Solitary fibrous tumor of the lung: a case report

Solitary fibrous tumors (SFTs) are relatively rare neoplasms that commonly occur in the pleura. The pathological feature of SFTs is a proliferation of spindle-shaped cells in interlacing or storiform fascicles. SFTs appear to derived from pluripotential submesothelial cells, but not the covering mesothelium. SFTs distinctively show diffuse staining for CD34 but lack staining for smooth muscle markers. We herein report a relatively rare case of a 68-year-old male patient without symptoms, who underwent resection for what was considered to be SFT.

Determinants of outcome of solitary fibrous tumors of the pleura: an observational cohort study

Background

Solitary fibrous tumors of the pleura (SFTP) are rare and their long-term outcome is difficult to predict, as there are insufficient data which allow accurate characterization of the malignant variant. Thus the aim of this study was to describe the outcome and possible determinants of malignant behavior of SFTPs.

Methods

Data were collected retrospectively from medical records of patients treated at the University Hospital Zurich from 1992 to 2012. Kaplan-Meier and Cox regression analysis were performed to define disease-free survival time (defined as survival without tumor-recurrence or tumor-related death) using the classical histo-morphological criteria (tumor size, localization, pedunculation, tumor necrosis or hemorrhage, mitotic activity and nuclear pleomorphism) and immunohistochemical parameters.

Results

42 patients (20 males) with SFTP (median (IQR) age 62 (56–71) years) could be identified. SFTP were associated with symptoms in 50% of all cases. Complete resection was achieved by video-assisted thoracic surgery or thoracotomy in 20 and 22 patients, respectively. Three SFTP-related deaths (7.1%) and four tumor recurrences (9.5%) were observed. Mean disease-free survival time was 136.2 (±13.1) months, and 2-, 5- and 10-year disease-free survival was 91%, 84%, and 67%, respectively. Mean disease-free survival inversely correlated with the mean tumor diameter, number of mitotic figures and proliferation rate (Ki-67 expression). Other criteria (tumor necrosis, atypical localization, sessile tumor, and pleomorphism) were not statistically significant prognostic parameters.

Conclusions

Patients with large SFTP with a high mitotic index and high proliferation rate should be followed-up closely and over a prolonged time period in order to recognize recurrence of the SFTP early and at a treatable stage. Future research on this topic should focus on the prognostic role of immunohistochemistry including Ki-67 expression and molecular parameters.

[Solitary fibrous tumour of the pleura: five cases]

Solitary fibrous tumours are unusual mesenchymatous tumours, most often found on the pleura. The authors report five cases hospitalised between 1998 and 2003. With the greatest occurrence in the fifth decade, they are often accidentally found but sometimes associated with a paraneoplastic syndrome such as refractory hypoglycaemia. The diagnosis is based on computed tomography and complete surgical resection is the best treatment. Adjuvant therapy is proposed for the histologically aggressive forms. Because of the possibility of local or distant recurrence and malignant transformation, long-term monitoring is strongly recommended.

[Solitary fibrous tumor of the retroperitoneum]

Solitary fibrous tumour is unusual, arising most commonly in the pleura and can also occur in a large number of other sites. We report the case of a 34-year-old man with a retroperitoneal solitary-fibrous tumour, revealed by abdominal pain and hypoglycaemia. We describe the histopathological and immunohistochemical features. Solitary-fibrous tumour should be included in the differential diagnosis of spindle cell tumours in this location. Despite complete local excision, local recurrence and metastasis are seen. The behaviour of theses tumours is unpredictable and patients with solitary fibrous tumour require careful and long-term follow-up.

Solitary fibrous tumors of the pleura: Immunohistochemical analysis and evaluation of prognostic factors after surgical treatment

BACKGROUND AND OBJECTIVES

Solitary fibrous tumors of the pleura (SFTP) are rare neoplasms with unusual histological and clinical features. Although surgery is the treatment of choice for SFTP, tumor recurrence may occur after complete resection, even in tumors with benign histological features. The aim of the study was to identify the clinical and pathological features of SFTP that are associated with a higher risk of recurrence after surgical treatment.

METHODS

From May 1995 to September 2002, 18 patients (10 female, 8 male; mean age 58 years) with SFTP underwent complete surgical treatment at our department. Mean follow-up was 61 months. Mean tumor size was 10 cm. The tumors were pedunculated in 10 patients and sessile in 8. Histological features were benign in 16 patients and malignant in 2.

RESULTS

Five-year disease-free survival was 80%. A higher incidence of tumor recurrence was observed when SFTP originated from the parietal pleura, had malignant histological features and a lower expression of progesterone receptors (P < 0.05).

CONCLUSIONS

Clinical and pathological characteristics, such as malignant histology, sessile morphology, and a lower expression of progesterone receptors identify SFTP with a higher risk of recurrence after surgery, and which thus require strict follow-up.

Localized fibrous tumors (LFTs) of the pleura: clinical data, asbestos burden, and syntactic structure analysis applied to newly defined angiogenic/growth-regulatory effectors

This study was performed to add clinical data, to introduce new markers, and to perform syntactic structural analysis on localized fibrous tumors (LFTs) of the pleura. The material comprised clinical data and processed sections obtained from 36 patients. The results achieved from quantitative imaging techniques and syntactic structure analysis were correlated with clinical data, including patients' habits (smoking), asbestos exposure, survival, and tumor recurrence. The disease caused increasing chest pain and dyspnea in 47% of patients. Exposure to asbestos was noted in 13 out of 36 patients, whereas smoking posed no major risk factor. Two patients developed a recurrent tumor after 8 and 42 months, respectively; none of the other patients died of this tumor disease within the follow-up period of maximal 212 months. The cases were clearly discriminated from mesotheliomas by the marker profile. Frequent expression of accessible ligands for endogenous lectins galectins-1 and -3, the expression of the angiogenic macrophage migration inhibitory factor (MIF), and the dense vascularization intimate a functional relationship. The proliferation index (Nv) was computed to be 1.6% in line with the balance of galectin expression. Abnormal p53 was expressed in only 19.4% of the cases. The diagnosis of LFT can be aided by quantitative assessment of vimentin, CD34, MIF, vascularization, and proliferation. Considering the galectin network, differential expression was noted with preference to effectors limiting growth and aggressiveness.

Biphasic solitary fibrous tumour: a report of two cases with epithelioid features

We present two cases of solitary fibrous tumour (SFT) showing biphasic morphology with a spectrum of malignant epithelioid components. Slides prepared from formalin-fixed and paraffin-embedded tissue from both cases were stained with haematoxylin and eosin and by immunohistochemistry. Interphase fluorescent in situ hybridisation studies were performed in both cases using paraffin-embedded tissue to look for the t(X;18) translocation, thereby to exclude synovial sarcoma. Both cases showed biphasic morphology with some areas having typical benign spindled SFT morphology (including CD34 expression) and other areas having a malignant epithelioid appearance. In one of the cases, the epithelioid area, which was well circumscribed and showed packeting of cell groups, demonstrated expression of cytokeratin and epithelial cadherin but not of CD34. In the second case, the immunophenotype of the epithelioid component was similar to that of the benign SFT component. These findings suggest that epithelioid change in SFT shows a range of differentiation at one end, similar to that of a standard SFT, and at the other end, possibly acquiring epithelial characteristics.

Localised pleural malignant mesothelioma. Report of two cases simulating pulmonary carcinoma and review of the literature

AIMS

To describe two cases of localised malignant mesothelioma with a predominantly intrapulmonary growth which led to a pre-operative diagnosis of pulmonary carcinoma.

MATERIALS AND METHODS

Both cases presented as intrapulmonary masses, while at computed tomography scan the pleura appeared not significantly thickened. In one patient, the main bronchus was diffusely infiltrated by the tumour. In both cases, a preoperative biopsy showed a proliferation of large cells leading to a diagnosis of non-small-cell lung carcinoma. Histological examination of the surgical specimens revealed features consistent with epithelioid mesothelioma with deciduoid features in one case and with biphasic mesothelioma in the other. Both cases were diffusely positive with anti-calretinin antibody, while anti-TTF1, anti-surfactant and anti-CEA antisera were negative.

CONCLUSIONS

Localised malignant mesotheliomas are unusual and predominantly intrapulmonary growth is rare. Pathologists should be aware of this possibility to avoid misdiagnosis, particularly in small biopsies.