Template:Oral and neck

Jaw cysts

Author: Mikael Häggström
Cystic changes in the jaw bones or around teeth:

Microscopic examination

Attempt to characterize the lining of the cyst. Look for important signs:

Signs

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  Cholesterol clefts: Indicates of a periapical (radicular) cyst or an inflamed dentigerous cyst.

Any keratinization of the lining.

Any signs of malignancy. Further information: Evaluation of suspected malignancies

Diagnoses

Relative incidence of odontogenic cysts.

All the following are odontogenic cyst, and in case of inability to specify further, may be simply diagnosed as such:

Cyst type	Lining epithelium	Other characteristics	Image
Periapical (radicular) cyst	Stratified squamous epithelium of variable thickness, except when originating in a maxillary sinus where there is respiratory epithelium (pseudostratified ciliated columnar epithelium).	A fibrous capsule of varying thickness, with chronic inflammatory cells, wherein a plasma cells may be abundant. They sometimes have the following features: Cholesterol clefts in the cyst lining.	Histopathology of a periapical cyst, with metaplastic changes of mucous secreting cells (B), and ciliated cells (C).
Non-inflamed dentigerous cyst	2 - 4 layers of cuboidal epithelium, devoid of superficial keratinization. Sometimes partially a thin, fragmented layer of eosinophilic columnar cells or low cuboidal epithelium	Typically: Fibrous to fibromyxoid connective tissue No rete ridges, flat interface They occasionally have: Dystrophic calcifications
Inflamed dentigerous cyst	Hyperplastic non-keratinized epithelium	Typically: Fibrous connective tissue Chronic inflammatory cells Sometimes: Elongated interconnecting rete ridges Cholesterol clefts, possibly cholesterol granuloma They occasionally have: Dystrophic calcifications
Residual cyst	Stratified squamous epithelium: May demonstrate exocytosis, spongiosis, and/or hyperplasia May be discontinuous in part and range in thickness from 1 to 50 cell layers, but usually 6 - 20 cell layers In early cysts, the epithelial lining tend to be proliferative and arcading, with an intense inflammation. Established cysts tend to rather have fairly regular lining with a higher degree of differentiation, resembling a simple stratified squamous epithelium	Cyst lumen may demonstrate fluid and cellular debris.

All types above can occasionally have scattered mucous or ciliated cells, as well as Rushton bodies, which are amorphic, eosinophilic, linear to crescent-shaped bodies in the cyst epithelium.

Report

• Type of lining
• Other visible features
• At least the most probable type of cyst.
• Even absence of signs of malignancy

Example:

Parts of a cyst, lined by stratified squamous epithelium, with foci of mucous cells and ciliated cells. The underlying fibrous capsule contains cholesterol clefts and inflammation. No signs of malignancy. - Benign odontogenic cyst of periapical type.

  See also: General notes on reporting

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Verrucous oral lesions

Author: Mikael Häggström

Verrucous hyperplasia.

Verrucous oral lesions have hypergranulosis and/or hyperkeratosis as the most conspicuous finding.

Microscopic evaluation

Look for signs of koilocyte-like changes, which may indicate verrucous squamous cell carcinoma, and which typically only has low atypia:

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Verrucous squamous cell carcinoma (images are from penis).

If uncertain, perform immunohistochemistry for Ki67 and p53.

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Tonsil

Author: Mikael Häggström

Comprehensiveness

On this resource, the following formatting is used for comprehensiveness:

• Minimal depth
• (Moderate depth)
• ((Comprehensive))

Gross processing

Gross pathology of a hypertrophic tonsil.

First look at the requisition form ((and in the medical records)) for the following suspicions:

• Suspected infection: Confirm that a sample has been taken for microbiology. If not, take a sample from within the specimen when you gross it.
• Possible lymphoma: Make a touch prep and take sample(s) for flow cytometry. If you have bilateral tonsils, and they look grossly similar, you may combine a small sample of each tonsil into one container for flow cytometry.
• Suspected tumor: Ink the external surfaces before sectioning. Otherwise inking is not needed. Further information: Tumor

Inspect the tonsils for any significant gross focal changes. A representative section of the grossly most abnormal part from each tonsil is generally enough.

Example gross report

((A. Labeled - ___. The specimen is received in formalin and consists of)) one rubbery, ovoid, pink-tan tonsil(s) measuring ____. The mucosal surfaces are unremarkable. On sectioning, the tissue is tan-white and homogenous, with no gross lesions. (Representative sections are submitted for microscopic examination in __ cassettes.)

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Nasal cavity

1. REDIRECT Nasal cavity and paranasal sinuses

Salivary glands

Author: Mikael Häggström, M.D.
The major salivary glands are the parotid, submandibular, and sublingual glands.

Evaluation

Look for the most common tumors:

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  Relative incidence of parotid tumors.

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  Relative incidence of submandibular tumors.

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  Pleomorphic adenoma (also called benign mixed tumor), H&E stain.

Cytology

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  Pleomorphic adenoma (Pap stain). It can usually be diagnosed by its typical fibrillary stroma (mesenchyme). Stromal cell nuclei are small. Myoepithelial cells are usually the predominant cell type, and can have various shapes but are usually more elongated than epithelial cells. Epithelial cells may have prominent nucleoli.

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  Warthin's tumor, with typical cellular features (and relatively uncommon binucleated cells). Pap stain. For a diagnosis, you should see sheets of oncocytes and a mixed population of lymphocytes.

Reporting=

Example report:

Right parotid mass, biopsy: – Pleomorphic adenoma.

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Thyroid

Fixation

Generally 10% neutral buffered formalin. Fix all thyroids at least overnight to avoid artifactual nuclear atypia.

  See also: General notes on fixation

Removal during autopsy

Parathyroid glands (white arrow), next to the thyroid gland.

Sharply dissect the thyroid from the cartilage, starting at the posterior end of each lobe & working forward. Do not cut the isthmus. Try to find parathyroids.

Gross processing of thyroidectomy

• Weigh. Up to 30 g versus over 30 g grams is an accepted cutoff between normal and increased weight of the thyroid gland.
• Measure each lobe and isthmus in 3 dimensions, respectively.
• Ink outer surface, at least if malignancy is suspected.

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  Hemithyroidecomy (lobe + isthmus) or lobectomy, including completion thyroidectomies: Use separate colors over the cut surface and the outer “capsular” or "peripheral" surface.

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  None of the outer “capsular” surface should be inked like the cut surface.

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  Intact total thyroidectomy: Separate colors for each lobe and the isthmus.

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  If no appreciable isthmus, Separate colors for each lobe.

((In addition, use different ink colors on the anterior versus posterior “capsular” or "peripheral" surface.))

Serially section the specimen at 3-4mm intervals, such as follows:

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  Hemithyroidecomy (lobe + isthmus) or lobectomy: Include isthmic orange margins in your transverse sections.

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  Intact total thyroidectomy: Transverse lobe sections and sagittal isthmus sections

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  Short/inconspicious isthmus: The isthmus can be included in the transverse sections.

  See also: General notes on gross processing

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  Thyroiditis, defined by a significant inflammatory infiltrate, usually lymphocytic.

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  Thyroid hyperplasia: Variable sized dilated follicles with flattened to hyperplastic epithelium. May form nodules, but without any significant capsule. Architecture resembles normal thyroid, but may be somewhat hypercellular.

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  Thyroid follicular adenoma, being architecturally and cytologically different from surrounding gland, and being completely enveloped by thin fibrous capsule (if not being encapsulated, mainly consider thyroid carcinoma if atypical cells, otherwise nodular hyperplasia with dominant nodule, the latter especially if there are hyperplastic changes elsewhere in gland). Hyperfunctioning follicular adenoma typically shows follicles with papillary infoldings and bubbly, pale colloid with peripheral scalloping (a). Non-hyperfunctioning adenomas with papillary hyperplasia usually show a more predominantly papillary pattern without vacuolated cytoplasm and scalloping colloid (b).

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  Hürthle cell adenoma, typically consisting of cells with large size, distinct cell borders, deeply eosinophilic and granular cytoplasm, large nucleus with prominent nucleolus, and complete loss of cell polarity.

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  Relative incidences of malignant thyroid tumors.

Papillary thyroid carcinoma

A papillary thyroid carcinoma is characterized by:

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  Pseudonuclear inclusions (representing cytoplasmic invaginations)

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  Nuclear grooves

Also, it typically has nuclei with:

• Enlargement, elongation, overlapping
• Chromatin with clearing, margination, glassy / ground glass texture
• Nuclear membrane with irregular contour

Other thyroid tumors

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  Follicular thyroid carcinoma, resembling follicular cells, and typically do not display the nuclear features of papillary thyroid carcinoma mentioned above. Distinction from adenoma requires invasion of adjacent thyroid parenchyma, capsule (complete penetration) and/or blood vessels (in or beyond the capsule).

Reporting

For cancers, generally include a synoptic report, such as per College of American Pathologists (CAP) protocols at cap.org/protocols-and-guidelines.

  See also: General notes on reporting

Papillary thyroid carcinoma

Evaluation

Papillary thyroid carcinoma, with typical features shown. Pap stain.

A papillary thyroid carcinoma is characterized by:

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  Pseudonuclear inclusions (representing cytoplasmic invaginations)

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  Nuclear grooves

Also, it typically has nuclei with:

• Enlargement, elongation, overlapping
• Chromatin with clearing, margination, glassy / ground glass texture
• Nuclear membrane with irregular contour

Staging

Staging as per AJCC, 8th edition:

Primary tumor (T)

T Category	T Criteria
TX	Primary tumor cannot be assessed
T0	No evidence of primary tumor
T1	Tumor ≤2 cm in greatest dimension limited to the thyroid
T1a	Tumor ≤1 cm in greatest dimension limited to the thyroid
T1b	Tumor >1 cm but ≤2 cm in greatest dimension limited to the thyroid
T2	Tumor >2 cm but ≤4 cm in greatest dimension limited to the thyroid
T3	Tumor >4 cm limited to the thyroid, or gross extrathyroidal extension invading only strap muscles
T3a	Tumor >4 cm limited to the thyroid
T3b	Gross extrathyroidal extension invading only strap muscles (sternohyoid, sternothyroid, thyrohyoid, or omohyoid muscles) from a tumor of any size
T4	Includes gross extrathyroidal extension beyond the strap muscles
T4a	Gross extrathyroidal extension invading subcutaneous soft tissues, larynx, trachea, esophagus, or recurrent laryngeal nerve from a tumor of any size
T4b	Gross extrathyroidal extension invading prevertebral fascia or encasing the carotid artery or mediastinal vessels from a tumor of any size

Regional lymph nodes (N)

N Category	N Criteria
NX	Regional lymph nodes cannot be assessed
N0	No evidence of locoregional lymph node metastasis
N0a	One or more cytologically or histologically confirmed benign lymph nodes
N0b	No radiologic or clinical evidence of locoregional lymph node metastasis
N1	Metastasis to regional nodes
N1a	Metastasis to level VI or VII (pretracheal, paratracheal, or prelaryngeal/Delphian, or upper mediastinal) lymph nodes. This can be unilateral or bilateral disease.
N1b	Metastasis to unilateral, bilateral, or contralateral lateral neck lymph nodes (levels I, II, III, IV, or V) or retropharyngeal lymph nodes

Distant metastasis (M)

M Category	M Criteria
M0	No distant metastasis
M1	Distant metastasis

Thyroid cytology

Author: Mikael Häggström

Adequacy

A minimum number of 6 clusters with 10 cells each has been arbitrary established to assume adequacy for a definitive diagnosis. The presence of characteristic cells may still confer a definitive diagnosis, but otherwise, the report will simply state inadequate number of cells.

Risk stratification

Papillary thyroid carcinoma, with typical features shown. Pap stain.

Look at least for the following imaged features, and classify findings as per the Bethesda system:

Bethesda system

Category	Description	Example report
I	Non diagnostic/unsatisfactory
II	Benign (colloid and follicular cells)	Thyroid aspiration, right upper pole: Negative for malignant cells. Clusters of benign follicular epithelial cells and colloid. Findings are consistent with a benign hyperplastic nodule. (Bethesda category II)
III	Atypia of undetermined significance (AUS) or follicular lesion of undetermined significance (FLUS) (follicular or lymphoid cells with atypical features)	Thyroid aspiration, right mid pole: Clusters of atypical follicular cells of undetermined significance (Bethesda category III).
IV	Follicular nodule/suspicious follicular nodule (cell crowding, micro follicles, dispersed isolated cells, scant colloid)
V	Suspicious for malignancy
VI	Malignant

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  Relative incidences of histopathologic diagnoses of solitary thyroid nodules that have undergone fine needle aspiration.

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  Cytology of benign follicular epithelial cells (Bethesda category II), Pap stain, showing cells with significant nuclear pleomorphism but otherwise insignificant features.

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  Look for microfollicles, which are flat groups of follicular cells, each having less than 15 follicular cells arranged in a circle that is at least two thirds complete. They indicate a follicular neoplasm.

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  Thyroid spherules, on the other hand, are benign features. A spherule may mimic a microfollicle, but has a more smooth, round, ball-like contour, and even spacing of the follicular cell nuclei.

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  Relative incidences of malignant thyroid tumors.

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  Cytopathology suspicious for Hürthle cell neoplasm (Bethesda category IV), Pap stain. However, it cannot distinguish Hürthle cell adenoma from Hürthle cell carcinoma, which requires histopathologic sections to see transcapsular or vascular invasion. Hürthle cell hyperplasia (as seen in Hashimoto's thyroiditis) may show moderate variation in nuclear sizes and prominent nucleoli, but further findings favoring Hürthle cell neoplasm include a large number of Hürthle cells, and discohesiveness.

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Parathyroid glands

Author: Mikael Häggström

Presentations

Intraoperative consultation

Necessary components are:

• Weight of the parathyroid gland or fragment thereof. Generally, there should not be any subjective description of "enlarged" or similar.
• Presence of parathyroid tissue upon frozen section. In particular, exclude sampling from the thyroid. It is not necessary to specify any particular parathyroid pathology on intraoperative consultation (which in case of hyperparathyroidism relies on imaging and intraoperative parathyroid hormone levels rather than the histopathology).

Autopsy

Optionally for a comprehensive autopsy, or where there is suspicion of parathyroid pathology, an effort is made to find the parathyroid glands, and inspect them for general or focal hyper-/neoplasia.

Microscopic evaluation

The main conditions to look for and distinguish are:

• Parathyroid hyperplasia: Typically involves all 4 glands with diffuse enlargement.
• Parathyroid adenoma: Typically nodular growth with compressed rim of normal tissue.

Either is indicated by a decreased amount of intra-gland adipose tissue, and increased weight. A weight of 35-160 mg is above average but not in itself "enlarged" in the absence of other findings.

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  Histology of the parathyroid glands

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  Parathyroid chief cell hyperplasia: An increase in the parenchymal cell mass,as a result of the proliferation of chief cells, oncocytes, and transitional oncocytes in multiple parathyroid glands.

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  Parathyroid adenoma, with chief cells and eosinophilic follicles

• Parathyroid adenoma, fine needle aspiration

Microscopy report

Example for an intraoperative consultation:

A. Left inferior parathyroid, excision: 24 mg of parathyroid tissue. C. Right superior parathyroid, excision: 14 mg of parathyroid tissue.

Whenever possible, make a single report for multiple fragments from the same location. Example of final report, including additional fragments from the same locations:

A,B. Left inferior parathyroid gland, excision: Hypercellular parathyroid gland (121 mg aggregate weight), consistent with parathyroid hyperplasia. C,D. Right superior parathyroid gland, excision: Parathyroid gland (94 mg aggregate weight) without significant histopathologic changes. E. Left superior parathyroid gland, excision: Hypercellular parathyroid gland (142 mg aggregate weight), consistent with parathyroid hyperplasia. F. Right inferior parathyroid gland, excision: Hypercellular parathyroid gland (85 mg aggregate weight), consistent with parathyroid hyperplasia.

Normal example in autopsy:

Sections show <<1, 2, 3, 4>> parathyroid glands with no focal changes or signs of hyperplasia.