Sclerosing lipogranuloma (SLG) is a rare, reactive lesion, with both primary idiopathic and secondary traumatic origin, composed by granulomatous inflammation consequent to injury of the adipose tissue.
Sclerosing lipogranuloma is a rare lesion, with most cases reported as secondary to foreign material injection of oil-based substances in the external genitalia. Idiopathic cases are exceeding rare (Ricchiuti et al. 2012; Ohtsuki et al., 2007; Foxton et al., 2011; Singam et al. 2010).
Sclerosing lipogranuloma can occur at all ages. In particular, if the lesion is secondary to injection of foreign substances, it is more likely to occur in young adults (Ricchiuti et al. 2012; Ohtsuki et al. 2007; Foxton et al. 2011; Singam et al. 2010).
The lesion typically occurs in male genital region.
Treatment options can be divided into conservative and surgical. The conservative treatment comprises a close observation of the patients or the use of antibiotics or steroids, which are very effective. Surgical treatment can be performed as partial or complete mass excision (Singam et al. 2010). It seems that a combination of corticosteroid and subsequent excision could be the optimal therapeutic strategy (Ohtsuki et al. 2007; Singam et al. 2010). In some cases of secondary SLG, the evacuation of foreign substance is mandatory (Foxton et al. 2011).
The lesion is benign and self-limited, sometimes with spontaneous regression after biopsy or incomplete excision. However, in the latter case, early recurrence may also be seen (Ohtsuki et al. 2007; Singam et al. 2010).
At low power, in the dermis or subcutaneous fibroadipose tissue, multiple granulomas composed of multinucleated giant cells, foamy histiocytes and epithelioid cells of foreign body type are seen, usually associated with eosinophil infiltration in cases of primary SLG.
At higher magnification, the multinucleated cells tend to have degenerated lipids in their cytoplasm, which are seen as fine foldings of membranous structures.
If the lesion is secondary to the injection of substances, degeneration of elastic fibers, collagenization of neurovascular bundles, and endarteritis are present in the background, in association with pseudo-cystic spaces sometimes filled with lipid foreign material (Ricchiuti et al. 2012; Ohtsuki et al. 2007; Foxton et al. 2011; Singam et al. 2010).
Multinucleated giant cells and epithelioid cells stain positive for CD68, indicating their histiocytic origin. The lymphocytic infiltrate is composed mostly by T cells, in association with S100 positive dendritic cells.
The differential diagnosis with infectious and malignant conditions is based on clinical examination, since the microscopic features are quite characteristic of granulomatous reaction. If the lesion involves the testis, an immunohistochemical panel comprising PLAP and gamma-glutamyl transpeptidase may be necessary to differentiate this lesion from a germ cell tumor (Ricchiuti et al. 2012; Ohtsuki et al. 2007; Foxton et al. 2011; Singam et al. 2010).
References and Further Reading
- Singam, P., Suriyani, L., Ho, C., Eng Hong, G., & Zainuddin, Z. (2010). Primary sclerosing lipogranuloma: An unusual scrotal mass. Libyan Journal of Medicine, 4, 5.Google Scholar