Contemporary management and classification of hepatic leiomyosarcoma

Abstract

Background: Hepatic leiomyosarcomas are rare soft-tissue tumours. The majority of lesions previously considered as leiomyosarcomas have been identified as gastrointestinal stromal tumours (GISTs). Consequently, understanding of the role of liver resection for true leiomyosarcoma is limited, a fact that is exacerbated by the increasing recognition of leiomyosarcoma subtypes. This study presents data on the outcomes of liver resection for leiomyosarcoma and suggests an algorithm for its pathological assessment and treatment.

Methods: Patients were identified from a prospectively collected departmental database. All tumours were negative for c-kit expression. Immunohistochemistry was performed to identify the presence of oestrogen or progesterone receptor (OR/PR) expression or Epstein-Barr virus (EBV) and patients were stratified according to this profile.

Results: Eight patients (of whom seven were female) underwent a total of 11 liver resections over a 12-year period. One patient had a primary hepatic leiomyosarcoma. Of those with metastatic leiomyosarcomas, the primary tumours were located in the mesentery, gynaecological organs and retroperitoneum in four, two and one patient, respectively. Both leiomyosarcomas of gynaecological origin stained positive for OR/PR expression. One patient had previously undergone renal transplantation; this leiomyosarcoma was associated with EBV expression. Median survival was 56 months (range: 22-132 months) and eight, six and four patients remained alive at 1, 3 and 5 years, respectively.

Conclusions: Hepatic resection for leiomyosarcoma is associated with encouraging rates of 5-year overall and disease-free survival. The worse outcome that had been expected based on data derived from historical cohorts (partly comprising subjects with GIST) was not observed. An algorithm for pathological classification and treatment is suggested.

Figure 1

Histopathology of a section of a leiomyosarcoma (not otherwise specified) demonstrates spindle cell malignancy with zones of necrosis typical of this tumour. (Haematoxylin and eosin stain; original magnification ×200)

Figure 2

Histopathology at higher magnification of a leiomyosarcoma (not otherwise specified) demonstrates mitosis, interlacing fascicles, pink cytoplasm and central cigar-shaped nuclei. (H&E stain; ×400)

Figure 3

Immunohistochemistry for desmin shows strong cytoplasmic positivity typically seen in smooth muscle. (Original magnification ×50)

Figure 4

Immunohistochemistry in a leiomyosarcoma of gynaecological origin shows positivity for nuclear oestrogen receptor expression (Original magnification ×400)

Figure 5

Polymerase chain reaction analysis (PCR) is positive for Epstein–Barr virus (EBV). *EBV is detected (dilution 1/5, 1/10 and 1/20) in patient 8 as confirmed by the positive and negative controls. The positive control is indicated by the arrow

Figure 6

Proposed algorithm for the pathological classification and management of abdominal smooth muscle tumours (SMTs) based upon histological assessment. Immunohistochemistry permits the stratification of SMTs into subgroups with implications for the patient's clinical management whereby gastrointestinal stromal tumours (GISTs) and gynaecological leiomyosarcomas may be treated with medical therapy, and Epstein–Barr virus (EBV)-related leiomyosarcoma by modifying immunosuppression. Primary and metastatic disease should be treated by surgical resection where possible. OR/PR, oestrogen/progesterone receptor