The histopathologic phenomenon of transepithelial elimination (TE), recorded by Pinkus1 in 1954 and later amplified by Mehregan,2 has been increasingly observed in a wide variety of dermatoses.
I recently saw a patient in whom lesions resembling perforating granuloma annulare developed following intralesional injection of triamcinolone acetonide sodium phosphate suspension into psoriatic lesions around the elbow. The histopathologic findings of TE were prominent in these umbilicated papules.
Goette DK. Transepithelial Elimination of Altered Collagen After Intralesional Adrenal Steroid Injections. Arch Dermatol. 1984;120(4):539-540. doi:10.1001/archderm.1984.01650400121028