Synovial sarcoma in older patients: clinicopathological analysis of 32 cases with emphasis on unusual histological features J A Chan, M E McMenamin & C D M Fletcher Department of Pathology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA Date of submission 1 November 2002 Accepted for publication 18 February 2003 Chan J A, McMenamin M E & Fletcher C D M (2003) Histopathology 43, 72–83 Synovial sarcoma in older patients: clinicopathological analysis of 32 cases with emphasis on unusual histological features Aims: To analyse the clinicopathological features of synovial sarcoma presenting in patients over 60 years of age, an uncommon subset which have not been specifically studied. Methods and results: Thirty-two cases of primary syn- ovial sarcoma in patients aged ‡60 years were retrieved from the authors’ consultation files. These were ana- lysed histologically and immunohistochemically and clinical follow-up was obtained in 26 cases (median duration 41 months). Mean age at diagnosis was 71.6 years (range 60–84) with 19 females and 13 males. Anatomical sites were lower limb (n ¼ 13), upper limb (n ¼ 5), lung ⁄ pleura (n ¼ 5), trunk (n ¼ 4), head ⁄ neck (n ¼ 3), mediastinum (n ¼ 1) and scrotum (n ¼ 1). Histologically, 23 were monophasic and nine were biphasic; 14 were poorly differentiated, of which five showed focally marked pleomorphism. Unusual features in two cases each included organoid nodules, granular cell change, squamous metaplasia and papillary architecture. Ten patients developed local recurrence and 11 developed metastases, of whom seven died. Large tumour size, poorly differentiated morphology and high mitotic rate correlated with poor outcome. Conclusions: Less than 10% of synovial sarcomas occur in patients over 60, in which age group this diagnosis is often not considered. Despite inevitable bias in consultation material, it seems that these cases, when compared with younger age groups, more often show poorly differentiated histology and more often develop at unusual locations. Keywords: synovial sarcoma, soft tissue, sarcoma, ageing Abbreviations: FISH, fluorescence in-situ hybridization; MFH, malignant fibrous histiocytoma; MPNST, malignant peripheral nerve sheath tumour; RT-PCR, reverse transcriptase-polymerase chain reaction; SS, synovial sarcoma Introduction Synovial sarcoma is a well-characterized and distinc- tive entity which comprises 5–10% of all soft tissue sarcomas. 1,2 Classically, it is a biphasic tumour con- sisting of epithelial and spindle cell components. 3 Monophasic types, composed solely of spindled cells or (exceptionally) epithelial cells, 4,5 and a poorly differentiated variant 6,7 were subsequently recognized, and it now seems that the monophasic spindle cell type is the most common. Although it may occur at any age, synovial sarcoma is typically a disease of ado- lescents and young adults, with peak incidence in the second to fourth decades; 90% of cases occur before the age of 50 years. 1,3 The vast majority arise in the extremities (85–90%) but a variety of unusual sites have also been documented. These locations include the head and neck region, 8,9 abdominal wall, 10 geni- tourinary tract, 11,12 chest wall ⁄ intrathoracic, 13–15 intraosseous, 16 intravascular, 17 intraneural 18 and intracranial 19 sites. Address for correspondence: Christopher D M Fletcher MD, FRCPath, Department of Pathology, Brigham and Women’s Hospital, 75 Francis Street, Boston, MA 02115 USA. e-mail: cfletcher@partners.org Ó 2003 Blackwell Publishing Limited. Histopathology 2003, 43, 72–83