glands are usually removed from patients with hypercalcemia. During the
re-moval of these glands, the surgeon often needs help identifying parathyroid
tissue, determining whether the parathyroid tissue is proliferative, and
distinguishing between hyperplasia involv-ing multiple glands and a neoplasm
confined to a single gland. For the surgical pathologist, these issues
translate into two simple questions that can be promptly addressed: (1) Is
parathyroid tissue present? (2) How large is the parathy-roid gland?
1. Is it parathyroid tissue?
Parathyroid glands areoval, encapsulated nodules that have a homo-geneous
red-brown cut surface. This gross appearance of the parathyroid is not specific
and may resemble a lymph node or a thyroid nodule. Fortunately, this
distinction can be made with speed and relative ease by resorting to frozen
section evaluation and/or with a touch imprint from the surface of the
2. How big is it? Perhaps the biggest
oversightwhen evaluating parathyroid tissue is for-getting to weigh the tissue.
While histologic examination is important in confirming the presence of a
parathyroid gland, the histologic findings may not reliably distinguish between
normal and proliferative parathyroid tissue. Instead, this distinction is best
made by weighing the gland. Therefore, it is critical that every specimen
potentially representing para-thyroid tissue be accurately weighed. Once an
enlarged parathyroid gland is removed, remain alert. Remember to weigh
additionalspecimens, since their size may be critical in distinguishing between
an isolated adenoma and diffuse hyperplasia.
these two questions in mind, the dissec-tion of parathyroid tissue is simple.
Measure and weigh the specimen, and note its gross appear-ance including its
shape and color. Use a scale that is accurate to the nearest milligram. If a
portion of the gland has been harvested by the surgeon for the purpose of
autotransplantation, ask the surgeon to estimate the weight of the gland that
was harvested and record this value in the gross report. Sometimes, instead of
a grossly apparent parathyroid gland, you may receive a portion of thyroid or
thymus. Because the parathyroids may lie hidden deep in the paren-chyma of
these organs, they should be rapidly yet thoroughly dissected and inspected. In
these cases, weigh the entire specimen before dis-secting it, and then weigh
the potential parathy-roid gland alone once any associated tissues have been
delicately removed. Bisect the parathyroid, and note the appearance of its cut
the intraoperative parathyroid hormone assay is being increasingly used
intra-operatively to guide the surgical management of primary
hyperparathyroidism, in many practices surgeons still request frozen sections
to confirm the removal of parathyroid tissue. Touch imprints of the cut surface
of the specimen (immediately fixed in 95% alcohol and stained with hematoxylin
and eosin) can be used to differentiate parathyroid from thyroid and lymphoid
tissue, and they often serve as a valuable adjunct to the frozen section.
addition to the parathyroid gland, remem-ber to sample other tissues that may
be part ofthe specimen (e.g., thyroid gland, thymus, and associated soft
tissues). Indeed, when these structures are removed in a search for an occult
parathyroid gland, the entire specimen should be submitted for histologic
evaluation if the para-thyroid gland is not grossly apparent. In the rare case
of a parathyroid carcinoma, sections should be submitted in an attempt to
document local inva-sion by the tumor. These sections should demon-strate the
relationship of the tumor to its capsule and to any adjacent structures (e.g.,
procedure was performed, and what structures/organs are present?
parathyroid tissue present? How many glands were removed?
• What is
the weight of each parathyroid gland (to the nearest milligram)?
• Based on
the comparative weights and histo-logic features, is the tissue most consistent
with normal parathyroid tissue, multiglan-dular hyperplasia, or an adenoma?
Keep in mind that the distinction between multi-glandular hyperplasia and an
adenoma re-quires correlation with the clinical and surgical findings.
parathyroid carcinomas: What is the size of the carcinoma? Does the carcinoma
extend beyond the tumor capsule? Is angiolympha-tic invasion present? Does the
carcinoma infiltrate into adjacent soft tissues and/or the thyroid? Are the
margins involved by tumor?