Diagnostic Pathology: Open Access
Open Access

In the diagnosis or exclusion of infectious disorders, the anatomic pathologist plays a critical role. The anatomic pathologist's initial responsibility is to evaluate the specimen to see if it has normal or abnormal histology (histopathology). If abnormalities are discovered, the pathologist will define the condition. Reactive or reparative diseases, dysplastic and neoplastic diseases, and inflammatory conditions, which include infectious diseases, are all classified using histologic and cytologic criteria. The classification of diseases has therapeutic as well as prognostic significance. A patient with a single lung nodule and a history of long-term smoking, for example, may have carcinoma.

Therefore, if an excisional biopsy reveals necrotizing granulomatous inflammation, a malignant tumour is eliminated and the look for an inflammatory or infectious cause begins. This isn't rare for a biopsies of a malignant tumor suspected of being cancerous to discover an infectious condition such as coccidioma, tuberculoma, or remains of the dog heartworm Dirofilaria immitis. In such cases, the anatomic pathologist may be solely responsible for the diagnosis of an infectious condition, as samples for culture are typically not acquired when a malignancy diagnosis is suspected.

In individuals from the southern United States, lung nodules considered to be coccidiomas, particularly those with a serologic response to Coccidioides immitis, carcinomas may be discovered. In an emergency, the histopathologist and cytopathologist may perform frozen-section analysis and fine-needle aspiration cytology, respectively, to make a fast morphologic diagnosis. Rapidly progressing disorders requiring immediate surgical debridement, such as rhinocerebral zygomycosis or necrotizing fasciitis sometimes necessitate frozen-section examination for infectious agents. The frozen section is useful in such conditions not only for diagnosis, but also for assessing the resection margins for acute inflammation and tissue damage.

Fine-needle aspiration can be utilised to examine aspirate specimens quickly, especially infectious lesion aspirate specimens. Palpable lesions can be aspirated by the pathologist or clinician, but deeper lesions require radiologic assistance. The fact that CTguided suction of deep-seated lesions does not require general anaesthesia is a benefit. Rapidly stained touch preparations and intraoperative cytologic diagnosis have also been found to be beneficial. The presence of a pathologist during the aspiration operation is beneficial for determining the adequacy of the specimen, which is frequently, assessed using air-dried diff-quik– stained smears. Because repeated aspirations may be conducted if diagnostic material is not obtained, this onsite quality assessment minimizes the incidence of non-diagnostic studies.

On the basis of the air-dried smears, the onsite pathologist may also provide a preliminary or conclusive diagnosis, as well as directing other studies such as culture. Due to the small amount of aspirated material, cytology-based prioritization of cultures based on the type of inflammation present may be beneficial. To offer optimal patient care, decrease waste, and prevent medical errors, collaboration between the anatomic pathologist and the microbiologist is required. Anatomic illness diagnosis can help clarify complex microbiologic cultures, whereas cultures can help disclose the identity of microorganisms found in tissue sections. The presence of bacteria in tissue sections aids the microbiologist in providing clinically relevant information and reducing the number of false reports. But, on the other hand, a comparable biopsy reveals invasive disease caused by a specific bacterium or fungus, the disease's origin becomes clearer, and the culture can be addressed accordingly. Furthermore, informing the microbiologist of the presence of microorganisms in tissue sections may enable the culture of finicky bacteria that demand special media or growth conditions.