Extrapleural solitary fibrous tumour

Definition

An extra-pleural (myo)fibroblastic tumour closely resembling pleural SFT. Previously, these tumours were commonly diagnosed as haemangiopericytomata.

Sites

This is a rare tumour, as common at extra-pleural sites as pleural²⁷, usually found in adults, rarely in children, at a large range of anatomical sites, which include:

subcutis (40% of cases)²¹, deep soft tissues^{12,13,14,15,20,21,22}, arm²⁵, back²⁵, nasal cavity^9,12,17,21, nasopharynx²¹, oral cavity¹⁸, tongue, larynx, salivary gland⁴, thyroid, orbit^2,7,12,13, meninges^11,13, lung^16,24, pericardium, mediastinum^16,24, breast , peritoneum^8,12,24, retroperitoneum^{12,13,15,22,24}, stomach, intestines, liver⁵, kidney^3,13,19, adrenal glands, periosteum⁶, spinal cord, testis, prostate^21,23, seminal vesicle^,23, bladder^21,23, vulva²², cervix¹³, skin

Clinical features

Large tumours may rarely give rise to hypoglycaemia by the secretion of an insulin-like factor. Rarely, there is nail clubbing²⁷.

Macroscopic appearances

Most tumours are well-demarcated. Malignant tumours may have infiltrative margins and show necrosis. The cut surface is usually firm and white; sometimes there is cyst formation or haemorrhage.

Histopathology

The histology is as for that of the pleural tumours. The presence of adipocytes produces overlap with lipomatous haemangiopericytoma and giant cell angiofibroma.

10-15 % show malignant behaviour. Malignancy is associated with increased cellularity, cytological atypia, 4 or more mitoses per 10 HPF and infiltrative margins. In rare cases, dedifferentiation gives rise to abrupt transition to a high grade sarcoma. Mediastinal, abdominal, retroperitoneum and pelvis are more likely to show aggressive behaviour.

Immunohistochemistry

CD34	95% (78/82)1, 12/1221, 7/922, 16/1618, 3/325
bcl-2	96% (72/75)1, 12/1218
CD99	31/311, 12/1221, 8/1218
vimentin	19/1910, 12/1221, 13/1318, 3/325
Factor XIIIA	10/1018
muscle-specific actin	0/510
desmin	0/510
SMA	2/12 (rare positive cells)18
S-100	0/1010
CD68	0/1010
cytokeratin	0/1910, 0/510

Related entities

Possibly part of the same spectrum are:

• Giant cell angiofibroma (orbital or extra-orbital)

• lipomatous haemangiopericytoma

Differential diagnosis

Very much dependent on anatomical site.

Deep fibrous histiocytoma

• myofibroblastoma (mammary and extra-mammary)

• pseudoangiomatous stromal hyperplasia of the breast

• metaplastic carcinoma

• monophasic synovial sarcoma

• malignant peripheral nerve sheath tumour

• leiomyosarcoma

• low grade myofibroblastic sarcoma

• dedifferentiated liposarcoma

• gastrointestinal stromal tumour

• dermatofibrosarcoma protuberans

• spindle cell thymoma

Prognosis

About 10% of extra-pleural tumours develop[ local or distant recurrence. Increased cellularity, more than 4 mitoses per 10 HPF, focal necrosis and cytological atypia correlate with malignant behaviour²⁷. Malignant cases metastasis to lung, bone and liver.

References

⁰World Health Organization Classification of Tumours, Tumours of Soft Tissues and Bone, IARC Press 2002.

¹Ordonez NG. Localized (solitary) fibrous tumor of the pleura. Adv Anat Pathol 2000;7:327-340.

²Dorfman, D. M., To, K., Dickersin, G. R., Rosenberg, A. E., Pilch, B. Z. Solitary fibrous tumor of the orbit. Am J Surg Pathol 1994;18;281-7.

³Gelb, A. B., Simmons, M. L., Weidner, N. Solitary fibrous tumor involving the renal capsule. Am J Surg Pathol 1996;20:1288-95.

⁴Gunhan, O., Yildiz, F. R., Celasun, B., Onder, T., Finci, R. Solitary fibrous tumour arising from sublingual gland: report of a case. J Laryngol Otol 1994;108:998-1000.

⁵Kottke-Marchant, K., Hart, W. R., Broughan, T. Localized fibrous tumor (localized fibrous mesothelioma) of the liver. Cancer 1989;64:1096-102.

⁶O'Connell, J. X., Logan, P. M., Beauchamp, C. P. Solitary fibrous tumor of the periosteum. Hum Pathol 1995;26:460-2..

⁷Westra, W. H., Gerald, W. L., Rosai, J. Solitary fibrous tumor. Consistent CD34 immunoreactivity and occurrence in the orbit. Am J Surg Pathol 1994;18:992-8.

⁸Young, R. H., Clement, P. B., McCaughey, W. T. Solitary fibrous tumors ('fibrous mesotheliomas') of the peritoneum. A report of three cases and a review of the literature. Arch Pathol Lab Med 1990;114:493-5.

¹⁰Brunnemann, R. B., Ro, J. Y., Ordonez, N. G., Mooney, J., El-Naggar, A. K., Ayala, A. G. Extrapleural solitary fibrous tumor: a clinicopathologic study of 24 cases. Mod Pathol 1999;12:1034-42.

¹¹Carneiro, S. S., Scheithauer, B. W., Nascimento, A. G., Hirose, T., Davis, D. H. Solitary fibrous tumor of the meninges: a lesion distinct from fibrous meningioma. A clinicopathologic and immunohistochemical study. Am J Clin Pathol 1996;106:217-24.

¹³Hasegawa, T., Matsuno, Y., Shimoda, T., Hasegawa, F., Sano, T., Hirohashi, S. Extrathoracic solitary fibrous tumors: their histological variability and potentially aggressive behavior. Hum Pathol 1999;30:1464-73.

¹⁴Suster, S., Nascimento, A. G., Miettinen, M., Sickel, J. Z., Moran, C. A. Solitary fibrous tumors of soft tissue. A clinicopathologic and immunohistochemical study of 12 cases. Am J Surg Pathol 1995;19:1257-66.

¹⁵Vallat-Decouvelaere, A. V., Dry, S. M., Fletcher, C. D. Atypical and malignant solitary fibrous tumors in extrathoracic locations: evidence of their comparability to intra-thoracic tumors. Am J Surg Pathol 1998;22:1501-11.

¹⁶van de Rijn, M., Lombard, C. M., Rouse, R. V. Expression of CD34 by solitary fibrous tumors of the pleura, mediastinum, and lung. Am J Surg Pathol 1994;18:814-20.

¹⁸Alawi, F., D. Stratton, et al. (2001). "Solitary fibrous tumor of the oral soft tissues: a clinicopathologic and immunohistochemical study of 16 cases." Am J Surg Pathol 25(7): 900-10.

¹⁹Wang, J., L. M. Weiss, et al. (2004). "Usefulness of immunohistochemistry in delineating renal spindle cell tumours. A retrospective study of 31 cases." Histopathology 44(5): 462-71.

²¹Mentzel, T., T. C. Bainbridge, et al. (1997). "Solitary fibrous tumour: clinicopathological, immunohistochemical, and ultrastructural analysis of 12 cases arising in soft tissues, nasal cavity and nasopharynx, urinary bladder and prostate." Virchows Arch 430(6): 445-53.

²²Nielsen, G. P., J. X. O'Connell, et al. (1997). "Solitary fibrous tumor of soft tissue: a report of 15 cases, including 5 malignant examples with light microscopic, immunohistochemical, and ultrastructural data." Mod Pathol 10(10): 1028-37.

²³Westra, W. H., R. T. Grenko, et al. (2000). "Solitary fibrous tumor of the lower urogenital tract: a report of five cases involving the seminal vesicles, urinary bladder, and prostate." Hum Pathol 31(1): 63-8.

²⁴Goodlad, J. R. and C. D. Fletcher (1991). "Solitary fibrous tumour arising at unusual sites: analysis of a series." Histopathology 19(6): 515-22.

²⁵Hasegawa, T., T. Hirose, et al. (1996). "Solitary fibrous tumor of the soft tissue. An immunohistochemical and ultrastructural study." Am J Clin Pathol 106(3): 325-31.

²⁶Chan, J. K. (1997). "Solitary fibrous tumour--everywhere, and a diagnosis in vogue." Histopathology 31(6): 568-76.

²⁷Graadt van Roggen JF, Hogendoorn PCW. Solitary fibrous tumour: the emerging clinicopathologic spectrum of an entity and its differential diagnosis. Current Diagnostic Pathology 2004;10:229-235.

This page last revised 5.7.2004.

©SMUHT/PW Bishop