Spindle Cell Tumours

Introduction

Spindle cells are of mesenchymal origin, and form the body's connective tissue, fat, muscle, bone, cartilage and blood vessels.

The name 'spindle cell' refers to the shape of the cell on cytology and histology.

Spindle cell tumours can be benign (suffix -oma) or malignant (suffix -sarcoma), 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

Haemangiopericytoma and Schwannoma

Diagnosis

Generally spindle cell tumours do not exfoliate well, although exceptions 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 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.

Sarcomas 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.

Spindle Cell Tumours Learning Resources
Flashcards Test your knowledge using flashcard type questions	Cytology Q&A 04 Cytology Q&A 17

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