General Guidelines for Intraoperative Consultations with Frozen Section

Historical Background

Although the frozen section technique was first used for routine intraoperative consultations in the late 19th century at Johns Hopkins Hospital and in the early 20th century at the Mayo Clinic, various methodologies to harden tissues for sectioning had been described almost a century earlier (Gal and Cagle, 2005; Wright, 1985). For example, a Dutch anatomist Pieter de Riemer developed a cold salt-and-water solution to freeze tissues in 1818, and other methods for freezing tissues for histology were described during the second part of the 19th century in England (Gal and Cagle, 2005; Gal, 2005). Dr. William Welch is credited with performing the first frozen sections intraoperatively in 1891 at Johns Hopkins Hospital, using a carbon dioxide freezing microtome. Ironically, in a situation that is well known to all surgical pathologists providing frozen section consultations, Dr. Welch’s breast surgeon, the famous Dr. William Halstead, completed his operation before the frozen section result was available (Gal, 2005). Dr. Thomas Cullen, also working at Johns Hopkins Hospital, is generally credited with the first written publication of the frozen section technique in 1895 (Gal, 2005).

The frozen section methodology was mostly popularized at the Mayo Clinic in Rochester, Minnesota, as the result of work of Dr. Louis B. Wilson, who became the chief of pathology there in 1905 and published a frozen section technique the same year (Wilson, 1905). Using a method that would be impossible to replicate in Los Angeles, he initially froze tissues by simply exposing them to -29 ºC outside winter air for a few minutes, cutting them by hand using a razor, mounting the sections on glass slides using a glucose mixture and staining them with methylene blue stain. Later on Dr. Wilson implemented the use of a Spencer automatic freezing microtome equipped with a carbon dioxide attachment and developed other standardized procedures that allowed Mayo pathologists to provide diagnoses within 5 minutes and often in as little as 2 minutes (Gal, 2005). Currently, the frozen section procedure can be performed using various refrigerated microtomes and other methods discussed in some detail in the next chapter.

Suggestions for Successful Intraoperative Consultations

Successful intraoperative consultations help guide the surgeon’s hand and procure adequate tissue.

The role of a surgical pathologist during intraoperative consultations is somewhat different than in other aspects of pathology practice (Lechago, 2005). In routine daily practice, pathologists are expected to provide an accurate and thorough interpretation of biopsies and other surgical specimens using a variety of methods that may include, in addition to hematoxylin-eosin–stained slides, immunohistochemistry and other ancillary tests. The frozen section, on the other hand, is a management tool to be used to address specific questions or problems that arise during surgery. It is not intended to be used as a shortcut to supplant the process of providing a comprehensive analysis of pathology specimens. The frozen section procedure is aimed at completing two important tasks: 1) help guide the surgeon’s decisions by answering as promptly and accurately as possible specific questions that vary according to the operation being performed, and 2) ensure that the tissues are procured and handled appropriately so that adequate tissue is obtained for diagnostic studies and additional prognostic and ancillary studies if indicated (Lechago, 2005; Kindschi, 1984). Although these two tasks are often not discussed explicitly during the performance of frozen section, they need to be kept in the mind of the surgical pathologist. For example, a thoracic surgeon who submits a lymph node obtained by mediastinoscopy may not write on the requisition form the frozen section indication. The surgical pathologist should nevertheless review the patient’s electronic medical records (EMR) or phone the surgeon to inquire about the indication for the procedure in order to determine proper tissue allocation. For example, if the patient is undergoing mediastinoscopy for lung cancer staging, all tissues need to be frozen and slides prepared from different tissue levels to exclude a metastasis; a nodal metastasis in an N2 lymph node from this patient will likely preclude a thoracotomy (Sienko et al, 2005). If metastatic carcinoma is present, the neoplasm likely will be tested with molecular methods, such as epithelial growth factor receptor (EGFR), and the pathologist must consider whether sufficient tissues remain available after the frozen section to perform these tests. If most of the tissue was exhausted during the frozen section procedure, the surgeon should be notified and additional lesional tissues requested. A second clinical scenario would be that of a patient undergoing a biopsy for mediastinal adenopathy. In this case, it is prudent to avoid exhausting the tissue during frozen section because additional studies such as flow cytometry may be required to evaluate for lymphoma or microbiologic cultures may be necessary to exclude an infectious granulomatous process from sarcoidosis.

Pathologists should not be timid about contacting the surgeon intraoperatively to disclose problems that may be relevant to patient care or to request that the surgeon perform certain tasks such as submitting sterile tissues for microbiologic cultures, procuring additional tissues for diagnosis or ancillary tests, and resecting additional tumor for margin assessment.