Intentional or accidental subcutaneous injection of paraffin or oily substances can result in subcutaneous fibroinflammatory deposits.
Injected material:
(1) vitamin E injection
(2) paraffin
(3) camphor or mineral oil
(4) petroleum lubricant (grease gun granuloma)
Reason for injection:
(1) therapeutic drug delivery
(2) cosmetic
(3) accident
(4) self-injected
Clinical features:
(1) indurated plaques and nodules
(2) The lesions may be tender.
(3) The lesions tend to be longstanding
Histologic features:
(1) Panniculitis with a "Swiss-cheese" appearance (round or oval spaces of varying diameter surrounded by fibrous tissue).
(2) Foamy macrophages and foreign body-type giant cells may be present.
(3) A frozen section of the lesion will stain positive with oil-red-O or other lipid stains.
