Incisional biopsy is partial tissue excision from a mass lesion for histopathologic studies without complete removal of the tumor. This type of biopsy affords an adequate tissue sample under direct visualization. Furthermore, if there is any doubt about whether the sample is representative, a frozen section can be performed intraoperatively; if that sample is not satisfactory, additional tissue can be obtained. Incisional biopsy must be performed as a surgical procedure and most of the time as an orbitotomy under general anesthesia.
The surgeon should be confident that the biopsy material is representative of the clinically abnormal tissue and should ensure that it is not crushed or cauterized during its removal. Therefore, wedge biopsy samples and tissue plugs of the tumor should be obtained expeditiously. The hemostasis of the area should be accomplished with pressure after the removal of the biopsy sample. In frozen sections, the cauterization of the base of the biopsy site should be done once it is certain that no other specimens from the same area will be obtained. Fragile tumors of certain types, such as lymphomas and soft mesenchymal tumors, are more prone to crush artifacts and therefore should be handled very gently with the forceps.
It is important for biopsy samples to be processed expeditiously by the circulating OR nurse, pathologist, or technician, particularly if any additional special procedures such as special tissue stains, im-munohistochemistry, cultures, gene studies, and flow cytometry are required. Most samples from incisional and excisional biopsies can be adequately evaluated by conventional histopathological methods of formalin fixation and staining with hematoxylin and eosin (H&E) and offer extra tissue for additional studies. However, in certain instances the clinical presentation, or a previous biopsy or frozen section diagnosis, may suggest to the surgeon and the pathologist the necessity of special studies. In these cases, it is wise to save fresh frozen tissue for future special studies. For example, if sebaceous gland carcinoma is suspected, the pathologist should be alerted at the time of the biopsy that a fat stain (oil red-O) may be needed and that a piece of fresh tissue for fat staining should be saved. Unfixed tissue must also be saved for the flow cytometry, molecular studies, and certain types of immunohistochemistry preparation. Most of the immunohistochemistry studies, however, can be done on formalin-fixed, paraffin-embedded tissue material. If numerous special studies are to be ordered from a single biopsy specimen, the on-service pathologist should be so advised and the tissue submitted "fresh,"
114 part two: diagnosis of orbital tumors
TABLE 12.1. Dos and Don'ts in Orbital Biopsy.
Fine-needle aspiration biopsy
Advise the pathologist and the radiologist if the lesion presents with atypical clinical features.
Do a quick frozen section on an unknown mass before it is totally submitted in formalin; fresh tissue may be needed for special studies and cultures.
Excise cystic lesions intact; a well-formed cystic lesion may be helpful for histopathologic examination.
Do not cauterize small mass lesions and do not let them dry out before fixation; cauterization and drying artifact may interfere with histopathologic evaluation.
Communicate with the pathologist.
Try to obtain a representative piece of the mass.
Do not cauterize the biopsy site or the bed of the biopsy site; cauterization artifact should be avoided if additional tissue is obtained.
Try to obtain at least a 2.5 cm segment of temporal artery for biopsy purposes, and let the pathologist know that the entire specimen should be serially sectioned.
Communicate with the pathologist.
Do not use large trephines through the skin, only through conjunctiva.
Make a small cut before using trephine/stylet complex through the skin.
Place firm pressure onto the orbit after the biopsy procedure, followed by ice compress for 24 hours.
Communicate with the radiologist/cytologist.
Be sure that enough tissue sample is obtained for all pathology studies.
If imaging reveals that the lesion is vascular, do not make too many passes with the needle and do not apply too much suction.
Place firm pressure onto the orbit following the biopsy procedure followed by ice compress for 24 hours.
Communicate with the pathologist; invite him/her to the operating room and/or examine the frozen section in the lab with the pathologist when necessary.
Orient the pathologist to the margins carefully, particularly on repeat tissues obtained from margins.
Do not use the Mohs technique in orbit cases; it is easy to lose track of the specimens while mapping a three-dimensional surgical field.
In recurrent tumor excisions, ask the pathologist to review previously removed tissues (if available).
Do not undertake major procedures (e.g., enucleation, exenteration) based on diagnosis of frozen sections; remember the limitation of the technique.
that is, in a sterile specimen container without formalin or any other fixative.
If margins of the tumor excision are to be determined on permanent sections, it is absolutely essen
FIGURE 12.1. Sampling skin ellipse: The conventional way of sampling of a skin tumor for frozen and permanent sections.
tial to devise a labeling scheme with numbers or letters to mark multiple biopsy specimens very carefully, and to list every single one on the pathology request slip (as specimen #1: inferior margin, specimen #2: inferior lateral margin, etc.).
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