Intraoperative Consultation (Frozen Section) in Parathyroid Gland and Parathyroid Proliferative Disease (PPD)/Hyperparathyroidism

Optimal management of primary hyperparathyroidism is achieved by selective removal of parathyroid glands guided by the histologic findings in each gland.

Surgical management of a patient with primary hyperparathyroidism is to remove one or more enlarged parathyroid glands.

Pathologists play a primary role in the clinical care of the patient.

At the time of parathyroid exploration the initial assessment of the excised tissue is the intraoperative histopathologic determination of whether the excised tissue is parathyroid tissue and, if so, whether it is or is not abnormal:

• In the majority of cases the identification of parathyroid tissue is rather simple, but at times this determination may prove difficult.

• It is well established that the differentiation of an adenoma from hyperplasia in a single enlarged gland cannot be made by histopathologic evaluation and that detailed clinical information (pre- and postoperative) is required to arrive at the diagnosis.

The most common developmental anomaly of the parathyroid glands is ectopia, which usually represents a variation in embryologic migratory pattern.

Parathyroid agenesis is very rare:

• DiGeorge syndrome includes complete or partial absence of the third and fourth pharyngeal pouches and their derivatives, including the thymus, the parathyroid glands, and thyroid C-cells.

  • –

    Manifests as multiple facial malformations, hypoplasia of the thyroid, hypoparathyroidism, and cardiac abnormalities

The parathyroid glands are soft yellow-brown to dark-brown, circumscribed, ovoid structures; some parathyroid glands are bilobed or flattened.

Each gland measures approximately 3 to 6 mm in length.

The combined weight increases from early infancy (mean, 5 to 9 mg) to the third or fourth decade (mean for males, 120 mg; for females, 142 mg).

The actual parenchymal cell mass represents about 74% of the weight of adult parathyroid glands.

The purpose of intraoperative consultation of patients with hyperparathyroidism is to determine the underlying pathologic process, which directly affects treatment.

A diagnosis of parathyroid adenoma results in excision of the involved gland alone, and this treatment is curative.

A diagnosis of parathyroid hyperplasia results in subtotal parathyroidectomy (three and a half glands), leaving behind a small amount of parathyroid tissue (approximately 50 g).

A diagnosis of parathyroid carcinoma usually necessitates en bloc resection to include the involved gland and adjacent thyroid lobe with or without selective neck dissection; this approach offers the best opportunity for a cure.

Surgeons' expectations include:

• Identify the tissue as being of parathyroid gland origin.

• Attempt to differentiate a parathyroid adenoma from hyperplasia.

• Identify carcinoma.

• Do this all in a short time period.

First rule in the intraoperative consultation of parathyroid diseases is “do not believe the surgeon that the resected tissue is of parathyroid gland origin.”

Second rule, which is mutually inclusive of the first rule, is to recognize the resected tissue as parathyroid parenchyma:

• Once recognized as parathyroid tissue, the determination of whether the resected tissue is normal, abnormal, or indeterminate can be undertaken (see Table 34-1 ).

Record location of excised tissue.

Record the size and weight of the excised glands after removing the surrounding fat (inform surgeon of these findings):

• Glands weighing greater than 60 mg are considered pathologic, whereas a normal gland typically weighs 35 mg.

• Do not remove fat that is closely apposed to any nodules because this tissue may be representative of a cap of normal parathyroid tissue, a potential key histologic feature in the diagnosis of parathyroid adenoma.

Gross examination with attention to the external appearance, color, and consistency of the excised gland

Perform frozen section.