Spindle Cell Tumours
Introduction
Spindle cells are of mesenchymal origin, and form the body's connective tissue, fat, muscle, bone, cartilage and blood vessels.
Spindle cell tumours can be benign or malignant, and will arise from these different cell lines.
It can be difficult to differentiate between the different forms of spindle cell tumours, and also to distinguish between spindle cell neoplasia and a fibroplastic spindle cell proliferative response.
Connective tissue tumours
Fibroma and Fibrosarcoma
Myxoma and myxosarcoma
Tumours of fat
Lipoma and liposarcoma
Tumours of muscle
Leiomyoma and leiomyosarcoma
Tumours of the blood vessel endothelium
Haemangioma and Haemangiosarcoma
Tumours of the lymphatics
Lymphangioma and lymphangiosarcoma
Other tumours
Diagnosis
Generally spindle cell tumours do not exfoliate well, although exception exist.
On cytological examination: cells are individual rather than adherent, fusiform, and with indistinct cell borders. Nuclei are often fusiform as well and cytoplasmic tails may fade into the background. It may be possible to determine the tissue of origin if there is evidence of collagen, cartilage, bone, fat or myxomatous material formation by the tumour cells.
Often, a diagnosis of spindle cell tumour is as specific a diagnosis as can be made.
Common cytological findings for benign spindle cell tumours include: small spindle-shaped cells, small nuclei, minimal anisocytosis.
Cyological findings for soft tissue sarcomas include:
- large, plump spindle cells
- large nuclei and prominent nucleoli
- prominent nuclear variability
- multinucleated giant cells
- pink extracellular stroma
Spindle cell proliferation occurs as a fibroplastic response in granulomatous inflammation, and this may be impossible to differentiate from benign or malignant neoplasms.
A biopsy and histopathology are usually necessary to confirm the diagnosis.
Treatment and prognosis
Benign forms are usually well circumscribed and can be surgically removed with an excellent prognosis.
Malignant forms are often highly infiltrative and locally aggressive, with a high likelihood of recurrence. Wide surgical excision is the treatment of choice.
They metastasise rarely (apart from haemangiosarcomas).
In all cases, a rapid and accurate diagnosis is important for treatment and prognosis.
References
Bond, R. (2009) Skin Neoplasia RVC student notes
Jackson, M. (2007) Veterinary clinical pathology Wiley-Blackwell
Freeman, K. (2007) Self-assessment colour review of Veterinary Cytology Manson Publishing