Materials and methods: An archival number of 30 cases of LCH type of PG and 26 cases of non LCH type of PG with complete patient's records were retrieved and retrospectively studied. Sections were stained with H-E and for the detection of CD34, a-SMA and MSA antigens. In LCH type of PG an ulcerative and lobular area were distinguished whereas in non LCH type an ulcerative and central area. In each of these areas the percentage of blood vessels with luminal diameter 10µm or smaller and 11-20µm was evaluated.
Results: Clinically, LCH type of PG more frequently (66.7%) occurred as sessile lesion whereas non LCH type as pedunculated (77%). Non LCH type was associated with etiologic factors more frequently (86.4%). In the lobular area of LCH type 18±5.2% of vessels were 11-20µm in the luminal diameter and 62±13.2% were 10µm or smaller, whereas in the central area of non LCH type of PG the frequency was 31.5±8.1% and 28.1±11.2% respectively. In the central area of non LCH type a significant greater number of vessels with perivascular mesenchymal cells non reactive to a-SMA and MSA was present than in the lobular area of LCH type of PG.
Conclusion: The results of the present study showed that there are clinical, histological and immunohistochemical differences between LCH type and non LCH type of PG. These differences could suggest that the two histological types represent distinct entities.