Carcinoma Adenoideo Quistico

Histologic Grading of Adenoid Cystic Carcinoma of the Salivary Glands
PHILIP A. SZANTO, MD,’ MARIO A. LUNA, M D , t M. EUGENIA TORTOLEDO, MD,t AND ROBERT A. WHITE, PHDt

Seventy-nine patients with adenoid cystic carcinoma arising in salivary glands were studied to determine whether a correlation existed between the morphologic features of the tumor and the prognosis. Three histologic gradeswere established: Grade I, tumors with tubular and cribriform areas but without solid components; Grade 11, cribriform tumors that were either pure or mixed with less than 30% of solid areas; and Grade 111, tumors with a predominantly solid pattern. Cumulative survival rates at 15 years were 39%, 26%, and 5%, for Grades I, 11, and 111, respectively. Grade 111 tumors were larger, recurred frequently,and killed the patients within 4 years. Grade I lesions were smaller, were amenable to complete surgical excision, and had a protracted clinical course. Grade I1 tumors lay between the other two forms both clinically and pathologically. Other important prognostic features of the adenoid cystic carcinoma were its primary site, its presence or absence at surgical margins, and the anatomicstructures it involved. Cancer 54:1062-1069, 1984.

a specific variant of adenocarcinoma of the salivary and mucous glands, has been recognized since 1853.’ In its most frequently seen histologic pattern, the majority of the cells are small and darkly stained with scanty cytoplasm. The cells are arranged in nests or sheets that are fenestrated by round or oval spaces, creating the characteristic“cribriform” design. Occasionally, the tumors have a predominantly solid cellular growth with a basaloid or anaplastic appearance that has few, if any fenestrations. The solid variant often demonstrates small areas of necrosis. Tubular structures with minimal stratification of the lining epithelium are often mixed with the classic cribriform and solid areas. Several authors have suggested that a solidhistologic pattern indicates a more serious prognosis than the cystic pattern. Stewart’ first noted the increased aggression suggested by the solid variant, although he credits the initial observation to Patey and T h a ~ k r a y . ~ Stewart described six cases. In two patients who died within 2 years, the tumors had a solid pattern of growth with larger cells than usual. Eneroth and associates4reported on 37 paDENOID CYSTIC CARCINOMA,

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t From the Departments of Pathology and Biomathematics, The University of Texas M. D. Anderson Hospital and Tumor Institute at Houston, Houston, Texas. * Current address: Department of Pathology, University of Health Science. The Chicago Medical School, North Chicago, Illinois. Address for reprints: Mario A. Luna, MD, Department of Pathology, M. D.Anderson Hospital and Tumor Institute. 6723 Bertner Avenue, Houston, TX 77030. Accepted for publication June 27, 1983.

tients with adenoid cystic carcinoma of the palate; 29 were highly differentiated, and 8 were poorly differentiated. All of the patients with poorly differentiated tumors survived less than 3 years. An earlier study by Eneroth on malignant tumors of the submaxillary gland5demonstrated the same dichotomy of behavior between the high-grade and the low-grade types of adenoid cystic carcinoma. Eby and coworkers,6 in a study of 54 patients with adenoid cystic carcinoma of the head and neck, found that a solid histologic pattern with areas of necrosis was seen in 7 of the 9 patients who had a fulminating course within three years of therapy. Perzin and others’ in 1978 identifiedan even more differentiated form of adenoid cystic carcinoma, the tubular variant, which apparently has an even better prognosis than the classic cribriform carcinoma. These investigators concluded “the tubular pattern should be separated as a subgroup which probably represents the best differentiated form of adenoid cystic carcinoma.” This observation was corroborated by the work of Chilla...