Pyogenic granuloma (PG) is a rather frequently encountered tumor and seldom arouses much concern. One of its uncommon complications is the recurrence of multiple satellite lesions following excision or irritation of the primary growth, that was called Pyogenic granuloma with satellite lesions (PGWSL) .
To date, 15 such cases have been reported in Japan. The original or the recurrent lesions usually showed a proliferation of angiomatous tissue usually found in PG. We report a case with many mitoses and high cellularity in histological feature and the pathogenesis of this uncommon entity is briefly reviewed.
Case report: The patient was a 21-year-old Japanese male who developed, for almost 1 month, a solitary rapidly growing, easily bleeding lesion on the left scapula. The lesion was pediculate, dark red in color, measured 25mm in diameter. About 3 months after local excision of primary lesion, many small, 1-3mm in diameter sessile vascular papules developed around the site of the original tumor. They were completely asymptomatic. The physical examination revealed no other abnormality. On clinical diagnosis of PGWSL, the involved area was completely excised and skin graft was done under general anesthesia. For 2 years after the operation, there has been no recurrence.
The histopathologic picture in satellite lesions showed a proliferation of capillary vessels immersed in an edematous and myxoid stroma in the dermis, which was usually found in normal solitary PG.
The primary lesion showed a proliferation of capillary vessels with a little nuclear atypia, deep extension, many mitoses, and higher cellularity compared with the histology of normal PG. These histological features suggest that these tumor cells have intermediate characters between benign and malignant cells.
Ultrastructural examination was carried out on the recurrent lesion and compared with normal PG. The nuclear envelopes of tumor cells were more irregular and they had much more rough endoplasmic reticulum than those of normal PG.
In immunohistochemical study, including factor VIII related antigen (Factor VIII), intercellular adhesion molecule-1 (ICAM-I), HLA-DR, endothelial leukocyte adhesionmolecule-1 (ELAM) and basic fibroblast growth factor (bFGF), no apparent differences could be observed between recurrent lesion of our case and normal PG.
In 16 cases of PGWSL reported in Japan, including this case, 9 patients were males and 7 females. Most were children or young adolescents and average age was 18. 14 cases had their lesions on the trunk and the other 2 had on their face. Five patients were treated with completely excision of the involved area as initial treatment of the recurrent lesion. In 8 cases, the lesions were simply excised or destroyed with cautery or appreciated with topical corticosteroid at first, while 2 of them were recurred and finally completely excised. Unfortunately the other 3 reported cases were not fully described about clinical treatment.
Although the recurrence of PGWSL runs a benign course and there is no evidence that the satellites show metastasis, we consider that complete excision of the involved area is the best method when the lesions recur repeatedly or histopathological picture shows some atypia such as our case. Although the etiology of the development of PGWSL remains unknown, we consider that this entity has much more activity than normal PG.
