CLINICOPATHOLOGICAL FEATURES OF VULVAR SQUAMOUS-CELL CARCINOMAS EXHIBITING PROMINENT FIBROMYXOID STROMAL RESPONSE

The frequency, distribution, and significance of a prominent fibromyxo id stromal response to tumor was examined in 51 consecutive cases of i nvasive squamous carcinoma of the vulva in which the lesion was totall y excised and follow-up information available. The stromal response co nsisted of an admixture of myxoid change and immature collagen with fi broblasts at the tumor-stromal junction and was seen focally (<25% of the tumor) in 11 of the 51 cases (21%), regionally (26-50% of tumor) i n seven cases (14%), diffusely (>50% of tumor) in eight cases (16%), a nd not at all in. 25 cases (49%). Tumors showing a prominent fibromyxo id stromal response (>25% of the tumor) were typically flat or elevate d ulcerative lesions, whereas carcinomas without a prominent fibromyxo id stromal response were more commonly exophytic. Sixty percent of the tumors with a prominent fibromyxoid stromal response involved the cli toris, compared with clitoral involvement in only 14% of carcinomas wi thout a prominent response. Cases showing prominent fibromyxoid stroma l response were associated with a significantly older age group, poore r survival rate, and more extensive lymph node metastases than when fi bromyxoid stromal response was not prominent, This behavior was manife sted despite the fact that these tumors were not larger, more deeply i nvading, of higher grade, or more likely to show infiltrating patterns of invasion than when fibromyxoid stromal response was not prominent. Because the ability of a tumor to invade is believed to be related in a large part to changes in the relationship of tumor to stroma, a cor relation between fibromyxoid stromal response and aggressive tumor beh avior would suggest that a specific pattern of alteration in the inter action of tumor cells with stroma occurs in a subset of vulvar squamou s carcinomas The current findings may reflect the diverse etiology of vulvar carcinoma. If the characteristic features of vulvar carcinomas showing a prominent fibromyxoid stromal reaction as shown in this stud y can be confirmed on larger study populations, ''squamous cell carcin omas with prominent fibromyxoid stromal reaction'' may be a useful des ignation for these tumors.