Technical note: A comparison between rehydrating solutions in the pretreatment of mummified and corified skin for forensic microscopic examination

Abstract

Microscopic examination of mummified or corified skin may be of extreme importance for forensic purposes. However, standard histological samples in these cases are low-end, and preparation is burdened by several problems and so are diagnostic results: an improvement of these types of specimens is therefore advantageous. This study aims to identify the best performing rehydration solution among a fabric softener, a body lotion, and Sandison's rehydrating solution. Samples of skin undergoing mummification or corification were collected from 25 corpses and each sample was divided into 4 fragments: one of these fragments was directly fixated in 4% formalin, one was previously treated with a tissue softener, another one was previously treated with a body lotion, and the last one was treated with Sandison's solution. After 72 h, the pretreated samples were post-fixated in 4% formalin and then prepared for standard histological examination staining the histological slides with hematoxylin-eosin and Masson's trichrome. At the microscopic examination, samples directly fixated in formalin were characterized by usual marked structural alterations and altered stainability, typical of such dry tissues. Vice versa, those previously treated appeared to be better-preserved even though with different improvement levels: body lotion made a medium-low-grade restoration of the tissues, and fabric softener a high-grade restoration, while Sandison's rehydrating solution produced an optimal grade restoration. Sandison's rehydrating solution was confirmed to be the best rehydrating substance for mummified and corified skin. Fabric softener could be, however, considered a valid substitute, being productive of high-grade microscopic yield.

Keywords: Body lotion; Corification; Fabric softener; Forensic pathology; Mummification; Sandison’s rehydrating solution.

Fig. 1

Laboratory procedure scheme performed on each skin sample

Fig. 2

Microscopic view of preparations obtained after direct fixation in 4% formalin with marked structural alterations and altered stainability of the different tissue portions caused by severe and persistent drying. A Case no. 4 (H&E, 50×). B Case no. 6 (TM, 50×). C, D Case no. 10 (H&E, 100×, and TM, 100×, respectively) with evidence of vital hemorrhagic infiltrates

Fig. 3

Microscopic view of preparations obtained after pretreatment with body lotion and then fixated in 4% formalin with the evidence of poor tissue restoration, permanence of some drying effects, and small connective areas still inverted and red stained. However, all histological structures are recognizable. A, D Case no. 17 (H&E, 50× and TM, 50× respectively). E Case no. 8 (TM, 50×). B, C Case no. 21 (H&E, 100× and 200×, respectively) with low restoration of the histomorphology, due to charring and corification. F Case no. 10 (TM, 400×), with suggestive areas of possible hemorrhagic micro-extravasation

Fig. 4

Microscopic view of slides obtained after pretreatment with the fabric softener and then fixated in 4% formalin with the evidence of a considerable reduction of destructive effects, better preservation of different tissue portions, and restoration of tissue stainability with the persistence of minimal inverted color areas. A Case no. 24 (H&E, 400×). D Case no.15 (TM, 100×). B, C Case no. 21 (H&E, 50× and 100×, respectively), in which an improvement of the histoarchitecture is observable with the evidence of heat injury signs both on skin and muscle. E, F Case no. 10 (TM, 50× and 100×, respectively) showing clear vital hemorrhagic infiltrates

Fig. 5

Microscopic view of preparations obtained after pretreatment with the Sandison and then fixated in formalin 4% with the evidence of a clear improvement and considerable reduction of structure alterations and artifacts with the complete restoration of the connective tissue stainability. A Case no. 3 (H&E, 50×). C Case no. 13 (TM, 50×). D Case no. 19 (TM, 50×). B Case no. 21 (H&E, 50×) with the evidence of ameliorative effect although with the evidence of heat injury signs. E, F case no. 10 (both TM, 50×) with the evidence of vital hemorrhagic infiltrates

Fig. 6

Comparative picture of the histological findings per specific skin layer that were documented after the three different pretreatments