Publication:

Recurrent pyogenic granuloma: an update

Background Given the fierce controversy about the nature of pyogenic granulomas, starting with its unfitting name and ending up with its ideal treatment modality, this paper tries to numerically identify some predisposing factors of recurrence.

Methods The literature was initially reviewed and a total of twenty recurrent cases of pyogenic granuloma were contrasted, on one hand, to their initial appearance. On the other hand, all are contrasted to a similar number of normal mucosa using three histochemical stains: Alcian blue, periodic acid-Schiff and Masson’s trichrome.

Results For all recurrent lesions, all specimens showed myxoid structure histologically even if their initial appearance had possessed a sparse myxoid structure. The age of recurrence has been correlated to the histochemical findings. For the Alcian Blue stain (AB), the value of t-test was 3.808840. The pertaining value of P was 0.000593. The result was significant at P ≤0.05. For the PAS stain, the value of t-test was 3.640327. The value of P was 0.000871. The result was significant at P ≤0.05. In Masson’s trichrome staining, the value of t-test was 3.100816. The value of P was 0.002942. The result was significant at P ≤0.05. Accordingly, all stains showed significant difference in fibrous content in the initial and recurrent lesions. Conversely, the count of both endothelial vessels and inflammatory infiltrates in the recurrent lesions were significantly lower than the primary precursors.

Conclusions Given that collagen fibers are continually degraded and resynthesized while proteolytic degradation occur outside the cells through the activity of enzymes called  matrix metalloproteinases (MMPs), it is suggested that MMPs -positively expressed by PAS reactions- account for the spacing of the fibrous stroma, allowing for reshaping the three dimensional structure of the connective tissue. Myxoid structures are certainly promoting recurrence either via excessive secretion of hyaluronic acids or unknown mechanisms. The undisputed fact is the presence of myxoid structures in all our reported recurrent cases. Both inflammatory cascade and endothelial proliferation have no vital role in the recurrence according to our morphometric results. Finally, PAS stain should give more details in examining PGs than the other recruited counterparts. Keywords: Recurrent pyogenic granuloma, PAS stain, Myxoid structures, Etiopathogensis