Comparison Between 70% Ethyl Alcohol and 10% Formalin as Fixative Mediums in Surgical Cooperation Campaigns: A Pilot Study.

BackgroundThe lack of adequate resources in international cooperation limits the study of surgical specimens. The literature on inexpensive and widely available fixation media is scarce.Materials and MethodsSpecimens were prospectively collected during a surgical cooperation campaign in Senegal, where a team from Spain provided surgical care to the local population. The lesions were fixed in parallel using 10% formalin and 70% ethyl alcohol. Hematoxylin and eosin (H&E) and immunohistochemical techniques (IHC) were performed. Histological images were independently evaluated by two senior and two junior pathologists through an anonymized questionnaire.ResultsThree surgical specimens were included: 1 lymphoid hyperplasia (3 H&E, 4 IHC), 1 seborrheic keratosis (2 H&E, 5 IHC), and 1 branchial remnant (2 H&E, 2 IHC). Fixation times were similar in all the specimens (10-13 days). All formalin H&E were diagnostic. Ethyl alcohol H&E was 100% diagnostic on 5/7 slides and 75% in the two remaining slides. In most slides, pathologists preferred formalin. Keratin 7, P40, EMA, keratin AE1/AE3, and TTF1 were 100% diagnostic in both groups. CD20, CD45, and EMA were 100% diagnostic in formalin and 75% diagnostic in ethyl alcohol. CD10 was 75% diagnostic in formalin and 25% diagnostic in ethyl alcohol. BCL6 was 75% diagnostic in formalin and 100% diagnostic in ethyl alcohol. IHC preferences were inconsistent.ConclusionsEthyl alcohol shows poorer fixation than formalin but enables diagnosis in most specimens. Immunoreactivity varies by tissue and stain. Further studies are needed to validate these results.