Ovarian malignant melanoma

Epidemiology

Malignant melanoma of the ovary is uncommon and usually metastatic. Primary melanoma may arise within a mature cystic teratoma.

Clinical features

Most women are of reproductive age. Most have metastases at other sites, in particular lung.

Macroscopic appearances

The tumour is usually unilateral.

Histopathology

Eight of twenty three cases were pigmented. The cells are usually epithelioid but may be spindled. A spindle cell pattern may be associated with follicle-like spaces filled with proteinaceous fluid, resembling a juvenile granulosa cell tumour. Nuclei sometimes appear grooved, as in granulosa cell tumour. There may be nuclear pseudo-inclusions.

Immunohistochemistry

	S-100	18/19 (the one negative case expressed all other melanocytic markers)
	HMB-45	17/20
	Melan A	13/15
	Tyrosinase	10/15
	Mitf	8/14
	Inhibin	3/14
	Calretinin	1/12

Differential diagnosis

• If grossly pigmented, steroid cell tumour of the ovary

• If epithelioid, germ cell tumours including dysgerminoma and yolk sac tumour, granulosa cell tumour. Granulosa cell tumour may express S-100. Conversely, some melanomas are positive for inhibin and calretinin.

• If spindle cell with follicle-like spaces, juvenile granulosa cell tumour, hypercalcaemic variant of small cell carcinoma, carcinoid or alveolar rhabdomyosarcoma.

Prognosis

Prognosis is poor, with most patients dying within two years.

References

¹Gupta, D., M. T. Deavers, et al. (2004). "Malignant melanoma involving the ovary: a clinicopathologic and immunohistochemical study of 23 cases." Am J Surg Pathol 28(6): 771-80.

This page last revised 14.7.2004.

©SMUHT/PW Bishop