During a colon resection, the surgeon found a lesion on the liver and requests an immediate analysis of the specimen. What type of specimen is this?

In this scenario, the correct answer is frozen specimen. During a colon resection, if a surgeon discovers a lesion on the liver and requests an immediate analysis, the intention is often to determine whether the lesion is cancerous or benign while the patient is still under anesthesia.

A frozen specimen is created by quickly freezing the tissue, allowing pathologists to perform a rapid assessment known as frozen section analysis. This technique allows for a swift diagnosis and helps guide the surgeon in making immediate decisions about further surgical intervention or treatment during the same operative session.

Fresh specimens, while also processed quickly, typically do not undergo pathological assessment in the same immediate manner as frozen sections. Fixed specimens are preserved in formalin or similar solutions and are used for standard histological examination but require more time for processing, making them unsuitable for immediate intra-operative decisions. Routine specimens are usually collected for later analysis and are not designed for immediate evaluation during surgery.

Thus, in the context of needing immediate information regarding the lesion, the request for a frozen specimen is the most appropriate choice.