Clinicopathologic analysis of 66 Japanese thin melanomas with metastasis of sentinel or regional lymph node.

BACKGROUND: Assessment of sentinel lymph node status is commonly performed in the treatment of cutaneous melanoma. However, there are no definite guidelines for thin melanomas with Breslow tumor thickness <1.0 mm, in part because thin melanomas are relatively infrequently positive for lymph node metastasis. METHODS: We analyzed the clinicopathologic relationship among tumor thickness, mitotic index, tumor infiltrating lymphocytes (TIL), tumor size, regional lymph node metastasis and prognosis in 66 Japanese patients with thin melanomas. Immunohistochemical evaluations for TIL were also performed. RESULTS: Thirty-one of the 66 melanomas were Clark level I without lymph node metastasis (0/31, 0%). In tumors of Clark level II or higher (35/66), there were five (14%) regional lymph node metastasis. Melanomas with two or more mitoses in 1 mm(2) per high-power fields showed higher frequencies of lymph node metastasis (2/3, 67%), compared to those with fewer than two mitoses (3/32, 9%). Tumors with intensive TIL that partially or completely surrounded the tumor revealed higher frequencies of lymph node metastasis (5/28, 18%), compared to those with none or slight TIL (0/7, 0%). The main components of TIL were CD8-positive T lymphocytes. No metastasized tumors were under 2.0 cm(2) . CONCLUSIONS: The presence of mitotic activity, large tumor size and an intense lymphocytic infiltrate should prompt sentinel lymph node biopsy in thin melanomas.

Apocrine cystadenoma and apocrine hidrocystoma: examination of 21 cases with emphasis on nomenclature according to proliferative features.

BACKGROUND: Apocrine cystadenoma (AC) and apocrine hidrocystoma (AH) have been used interchangeably in the literature to designate cystic lesions of apocrine glands. METHODS: We reviewed 21 cases with biopsies of apocrine cystic lesions diagnosed as AH or AC stained by hematoxylin and eosin. The following histological characteristics were recorded: (a) number of cysts, (b) predominant architectural growth pattern of cyst wall, (c) tumor circumscription, (d) nuclear atypia, (e) mitotic activity, counted per 1 mm2 and (f) Ki-67 staining pattern. RESULTS: Our findings clearly show that there is a non-proliferative group and a proliferative group among the lesions. In the non-proliferative group, one may see some structures that resemble papillary projections but lack a fibrous core. In the proliferative group, we found true papillae, and this change was associated with atypia, mitotic activity and increased Ki-67 staining. CONCLUSIONS: Apocrine cystic lesions with true papillary projections should be referred to as AC rather than AH, to emphasize the proliferative adenomatous growth and depicted by their frequency of cytological atypia and high mitotic activity. Furthermore, we suggest complete excision of AC that are proliferative tumors.

Low-risk and high-risk histologic features in conjunctival primary acquired melanosis with atypia: Clinicopathologic analysis of 29 cases.

The current World Health Organization classification of conjunctival melanocytic proliferations divides them into conjunctival nevi and invasive melanoma but, in contrast to other anatomic sites, does not recognize melanoma in situ. All atypical intraepithelial conjunctival proliferations are included in a heterogeneous category designated as primary acquired melanosis (PAM) with atypia. We performed clinicopathologic analysis of 29 cases of PAM with atypia. On the basis of histologic features and frequency of association with invasive melanoma and metastases, we were able to divide our cases into 2 histologic groups. The low-risk group (13 cases) included lesions composed of small to medium size melanocytes with high nuclear to cytoplasmic ratio and small to medium size hyperchromatic nuclei devoid of nucleoli showing predominantly single cell lentiginous growth pattern. Invasive melanoma occurred in only 2 cases from this group. None of these lesions metastasized. The second, high-risk group (16 cases), showed increased frequency of association with invasive melanoma (15/16 cases, 94%) and metastases (4/16 cases, 25%). These lesions were more heterogeneous architecturally but were all composed of melanocytes showing various degrees of epithelioid features such as abundant cytoplasm, vesicular nuclei, or prominent nucleoli. In 4 cases discrete areas showing high-risk and low-risk features were identified. All 4 lesions were associated with invasion. Our findings offer a practical approach for prognostically useful subclassification of PAM with atypia, which emphasizes cytologic features of intraepithelial conjunctival melanocytic proliferation.