Cryotherapy for conjunctival primary acquired melanosis and malignant melanoma. Experience with 62 cases.

Sixty-two patients were treated by some combination of cryotherapy and surgery with an average follow-up of 3.3 years for one of the following diseases: focal or diffuse flat conjunctival primary acquired melanosis (PAM) with atypia but without a nodule of melanoma (10 cases); unifocal malignant melanoma with or without focal or diffuse PAM (30 cases); and multinodular/multicentric melanoma with and without PAM (22 cases). Of the ten patients who had PAM with atypia, invasive nodules of malignant melanoma did not develop. A second treatment was required to control the disease in four of the ten patients with extensive or diffuse lesions, and one has mild persistent disease. Of the 30 patients with unifocal nodules of malignant melanoma, 27 remained free of recurrence after one treatment, and 2 are asymptomatic after two treatments. One patient with a thick nodule at presentation required a parotidectomy and radical neck dissection for cervical metastases after recurrence in the conjunctival sac. In the group of 22 patients with multinodular malignant melanoma, only two did not have recurrent disease after one treatment. Of those who received multiple therapies, seven remained free of recurrence for at least 2 years after the last treatment; regional or distant metastases developed in nine; four required exenteration; and eight died. Conjunctival adjunctive cryotherapy avoids exenteration in extensive lesions of pure PAM and in unifocal melanoma, but even after multiple therapies, multinodular malignant melanoma had a 45% rate of metastasis. Metastasis was related to the presence of PAM sine pigmento in four patients (microscopically but not clinically detectable PAM); to the location of the nodules (9 of 10 patients who experienced metastases had forniceal, palpebral, and/or caruncular nodules); to the thickness or depth of invasion of the nodules (greater than 2 mm); and to the development of intralymphatic spread ("in-transit" local metastasis) within the conjunctival sac in six patients. No metastases were encountered among patients with strictly limbal nodules and among five patients with invasive nodules composed of spindle cells in part or in toto. Therapeutic success in this spectrum of melanocytic proliferations is closely correlated with the clinical extent of the disease when initiating definitive therapy.