Bcl-2, CD34 and CD10 expression in basaloid follicular hamartoma, vellus hair hamartoma and neurofollicular hamartoma demonstrate full follicular differentiation.

Generalized basaloid follicular hamartoma syndrome (GBFHS) is a rare, recently-described, autosomal-dominantly inherited disorder that presents with disseminated milia, palmoplantar pitting, hypotrichosis and basaloid follicular hamartomas (BFH). BFH is a benign adnexal tumor that resembles basal cell carcinoma (BCC). In this study, we report two cases of GBFHS and stain BFH, a vellus hair hamartoma (VHH) and a neurofollicular hamartoma (NH) with CD34, bcl-2 and CD10 to characterize and compare the staining patterns of these follicular tumors. Standard immunohistochemistry labeling with CD34, bcl-2 and CD10 was performed on paraffin-embedded, formalin-fixed tissue sections of five BFH (four for CD10), one VHH and one NH. CD34 stromal staining was observed in all specimens. Bcl-2 stained the outermost cell layers of the basaloid nests in all specimens. CD10 stained the peritumoral stroma of all specimens. The BFH, NFH and the VHH showed CD10 staining of matrical cells. CD34 and CD10 stain peritumoral stroma of BFH, VHH and NH. Bcl-2 stains the outermost cell layer of these tumors. CD10 was also observed to stain matrical cells. These results show the similarities in differentiation between these benign follicular neoplasms and trichoepithelioma.

Concordant loss of heterozygosity of DNA repair gene, hOGG1, in melanoma in situ and atypical melanocytic hyperplasia.

BACKGROUND: One major risk factor for cutaneous melanoma is chronic sun-exposure and oxidative stress. Among various oxidative DNA damages, 8-oxoquanine is the most abundant and is potentially mutagenic if not sufficiently repaired. The human 8-oxoquanine DNA glycosylase 1 (hOGG1) gene specifically repairs 8-oxoguanine, and this gene shows frequent loss of heterozygosity (LOH) in human tumors. In this study, we investigate whether hOGG1 LOH occurs in melanoma in situ (MIS) and adjacent atypical melanocytic hyperplasia (AMH). METHODS: Twelve skin biopsies with MIS and adjacent AMH were included. DNA samples derived from manual microdissection of tissues were subjected to polymerase chain reaction amplification using three fluorescent-labeled microsatellite makers, followed by fragment analysis. RESULTS: Five of 12 cases were informative for both telomeric (3S1297) and centromeric (3S1289 or 3S1300) markers, bordering the hOGG1 locus. Among them, four (80%) MIS and three (60%) AMH showed hOGG1 LOH at both markers. CONCLUSIONS: These results shows that LOH at hOGG1 gene is associated with MIS and AMH and suggest that the hOGG1 gene may play a role in melanocytic tumor progression.

Pustulo-ovoid bodies of Milian in granular cell tumors.

BACKGROUND: Granular cell tumors (GCTs) are benign neural tumors with a distinct histologic appearance on light microscopy, characterized by eosinophilic cytoplasmic granules. Pustulo-ovoid bodies of Milian (POB) are larger granules surrounded by a clear halo. There have been no histologic studies to document their prevalence in GCT. METHODS: We examined the sections of 47 cases of GCT stained with hematoxylin and eosin to determine the frequency of POB within this tumor. POB were measured per 10 high-power fields (HPFs) and were divided into the following categories: less than 10 POB per 10 HPFs, 10-30 per 10 HPFs, 30-50 per 10 HPFs and greater than 50 per 10 HPFs. RESULTS: POB were present in 100% of the specimens examined. Eleven cases (23%) had between 1 and 9 POBs per 10 HPFs, twelve cases (26%) had between 10 and 29 POBs per HPFs, five cases (11%) had between 30 and 50 POBs per HPFs and nineteen cases (40%) had greater than 50 POBs per HPFs. When grouped according to clinical characteristics, there was an even distribution of POB by age, sex and site of the tumor. CONCLUSIONS: In our series, POB were present in varying numbers in all the tumors studied. They appear to represent the heterogeneity of the lysosomes, giving the appearance of large granules that have partially detached from the adjacent cytoplasm. POB are an easily recognizable component of GCTs.

A hybrid form of myeloid/NK-cell acute leukemia and myeloid/NK-cell precursor acute leukemia.

Natural killer (NK)-cell leukemia/lymphoma is a rare entity that has been defined only in recent years. In the Revised European-American Lymphoma and World Health Organization classifications, only the mature NK-cell malignancies are included. However, at least 3 types of precursor NK-cell neoplasms have been reported in the literature. These include myeloid/NK-cell acute leukemia, myeloid/NK-cell precursor acute leukemia, and blastic NK-cell lymphoma/leukemia. These leukemias are characterized by the presence of blasts, which express CD56, in the peripheral blood, bone marrow, lymph nodes, and/or extranodal tissues. We report a case that is morphologically consistent with myeloid/NK-cell acute leukemia but immunologically is myeloid/NK-cell precursor acute leukemia. This case is unique in its cutaneous presentation without involvement of the peripheral blood. Extensive flow cytometric studies were performed on the skin biopsy and bone marrow aspirate specimens, which included many markers that had not been tested before in these entities. The clinical implications of these findings are discussed.