The Morphologic Identification of Common Organisms That May Look Alike in the General Pathology Practice: A Brief Review

Surgical Pathologists often rely on morphologic features in identifying organisms in their general practice. The aim of this paper is to provide a brief practical and illustrated reference, comparing the morphologic features of organisms commonly encountered in the general practice of pathology. This comparison will focus on pairs of organisms that may look alike, resulting in diagnostic difficulties. These paired look–alike organisms include: Histoplasma Capsulatum versus Pneumocystis, Falciparum Malaria versus Babesia Microti, Pseudohyphae (of Candida) versus True Fungal Hyphae (of Aspergillus), Septate Hyphae (as in Aspergillus) versus Aseptate Hyphae (as in Mucor), Fungal Hyphae versus Artifact, and Antibiotic-Altered Bacteria versus Other organisms. Key distinguishing morphologic features are compared to help avoid diagnostic pitfalls.