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Pleomorphic Adenoma (Benign Mixed Tumor)

Definition and Epidemiology

• Age: Most common between the 3rd and 6th decades; average age 45 years
• Sex: Slightly more frequent in women
• Site distribution:
  • Parotid gland: >80% of cases (most common site)
  • Submandibular gland: less common
  • Minor salivary glands: relatively rare; most common site within the oral cavity is the hard palate
• Robbins & Kumar Pathologic Basis of Disease, p. 697
• Bailey and Love's Short Practice of Surgery 28th Edition, p. 861

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Pathogenesis / Molecular Biology

• All tumor elements (including those appearing mesenchymal) are thought to derive from myoepithelial or ductal reserve (stem) cells
• Radiation exposure increases risk
• Most cases involve chromosomal rearrangements causing overexpression of PLAG1, a transcription factor that promotes cell growth via growth factor receptor signaling pathways
• Cases lacking PLAG1 overexpression are often associated with HMGA2 gene mutations (encodes a DNA-binding protein)
• Robbins, Cotran & Kumar Pathologic Basis of Disease, p. 697

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Clinical Features

• Painless, slow-growing, mobile, well-defined solitary mass
• Gradual progression over many years; can reach enormous proportions if left untreated
• Usually located in the parotid tail (superficial lobe)
• Deep lobe tumors may present as a paratonsillar bulge
• No facial nerve involvement in benign disease

• Sudden increase in size
• Facial nerve palsy
• Pain

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Gross Pathology

• Well-demarcated, rounded/ovoid mass, rarely exceeding 6 cm
• Broad-based surface bosselations
• Cut surface: gray-white with myxoid and blue translucent areas of chondroid (cartilage-like) stroma
• Capsule is variable: may be thick and fibrotic, attenuated, or even incomplete (especially on the palate)
• Peri-capsular nodules may be present, attached by slender pedicles - simple enucleation risks detaching these, creating foci for recurrence
• Predominantly myxoid tumors can rupture during surgery, seeding the field and causing multifocal recurrences

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Histopathology

• Luminal cells: CK7 (strong and diffuse)
• Myoepithelial cells: p63, S-100, SOX10, SMA

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Recurrence

• Robbins, Cotran & Kumar Pathologic Basis of Disease, p. 697

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Malignant Transformation - Carcinoma ex Pleomorphic Adenoma

• Older patient age
• Male sex
• Long duration of the tumor
• Multiple recurrences
• Deep lobe parotid location

• Robbins, Cotran & Kumar Pathologic Basis of Disease, p. 697
• Scott-Brown's Otorhinolaryngology Head & Neck Surgery

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Treatment

• Standard: Superficial or total parotidectomy with a cuff of normal tissue around the tumor to include the pseudopods
• Enucleation alone is contraindicated due to high recurrence risk from pericapsular extensions
• Minor salivary gland (oral cavity) tumors: Complete transoral excision; recurrences are rare with complete excision due to encapsulation
• CO2 laser is also used as a cutting tool for intraoral lesions

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Summary Table

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Clinical Examination of Pleomorphic Adenoma

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1. History (Pre-Examination Clues)

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2. Inspection

Position of the Swelling

• Parotid region: Fullness below and anterior to the ear, lifting the ear lobe - the classic sign that the swelling arises from the parotid gland
• Overlying skin: Normal in color and texture; no ulceration, fixation, or redness (these suggest malignancy)
• Facial symmetry: Check for any distortion of the face or obvious asymmetry

Specific Inspection Points

• Earlobe sign: The ear lobe is elevated/pushed outward by the swelling - pathognomonic of parotid origin
• Trismus: Absent in benign PSA (deep lobe tumors can impair jaw opening if very large)
• Open-mouth inspection: Deep lobe tumors may present as a paratonsillar or soft palate bulge (visible only with mouth open)
• Accessory parotid tissue tumors: Only visible when the patient opens the mouth (coronoid process pushes tumor outward)
• Minor salivary gland (palate/buccal mucosa): Smooth, sessile, submucosal swelling - most commonly on the hard palate

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3. Palpation

Characteristics on Palpation

Bimanual Palpation (for deep lobe / paratonsillar extension)

• One finger intraorally against the tonsil/soft palate, other hand externally over the parotid region
• A deep lobe PSA will be felt between both fingers as a firm mass in the parapharyngeal space
• Important to distinguish from a primary parapharyngeal tumor

Palpation of the Oral Cavity (Minor Salivary Gland PSA)

• Smooth, firm, non-tender, submucosal swelling
• Most common on the hard palate - typically posterior and lateral
• Freely movable in early stages; may be fixed to palate mucosa (does NOT imply malignancy - simply related to location)

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4. Facial Nerve Assessment (Critical)

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5. Regional Lymph Nodes

• Palpate the parotid/periparotid nodes, upper deep cervical chain, and jugulodigastric nodes
• In benign PSA: no palpable lymphadenopathy
• Lymphadenopathy suggests malignancy (carcinoma ex PSA) or a different primary diagnosis altogether

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6. Intraoral Examination

• Open mouth widely - look for paratonsillar bulge (deep lobe PSA)
• Inspect the Stensen's duct orifice (opposite upper 2nd molar): secretions should be clear; turbid/purulent discharge suggests infection not tumor
• Bimanually palpate submandibular and sublingual glands if the swelling is in that territory

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7. Complete Head and Neck Examination

• Contralateral parotid: Check for bilateral disease (rare in PSA; common in Warthin's)
• Submandibular glands: PSA can arise here; bimanual palpation required
• Skin: Any skin changes, fistulae, or previous scars

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8. Examination Summary: Classic PSA vs. Red Flags

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9. Special Notes

• Calcification on imaging (CT/USS): presence of calcification within a parotid or parapharyngeal mass strongly suggests pleomorphic adenoma - no other salivary tumor calcifies in this way
• Submandibular PSA: Must bimanually palpate; risk of marginal mandibular nerve injury at surgery is higher here
• Accessory parotid PSA: Felt as a mass along the line of Stensen's duct, anterior to the main gland; only moves forward when the patient opens the mouth (coronoid displacement)

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Clinical Examination of Pleomorphic Adenoma

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Step 1: General Observation (From the End of the Bed)

• A visible swelling in the pre-auricular/parotid region, below the ear, pushing the ear lobe upward and outward
• No obvious facial asymmetry from nerve weakness
• Patient typically appears comfortable and in no distress (painless condition)
• Assess whether the swelling is unilateral or bilateral

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Step 2: History Points that Guide Examination

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Step 3: Inspection

Site and Extent

• Swelling below and in front of the ear, at the parotid tail
• The ear lobe is elevated and pushed outward - this is pathognomonic of parotid origin
• The swelling fills the space between the mastoid process posteriorly and the ramus of mandible anteriorly
• Lower border may extend toward the upper neck

What to Note on Inspection

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Step 4: Palpation

Approach

• Warm hands
• Stand to the side and slightly behind the patient
• Use both hands to compare both sides
• Always palpate gently first

Characteristics to Elicit

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Step 5: Facial Nerve Assessment (MANDATORY in All Parotid Swellings)

Any facial nerve palsy = red flag. In benign PSA, the facial nerve is ALWAYS intact. Facial palsy strongly indicates malignancy - either carcinoma ex pleomorphic adenoma or a primary malignant tumor.

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Step 6: Intraoral Examination

Parotid Assessment Intraorally

1. Stensen's duct orifice - opposite the upper 2nd molar tooth (parotid papilla):
   • Massage the gland from behind forward
   • Clear saliva should flow freely = normal
   • Turbid or purulent discharge = sialadenitis/sialadenosis (not PSA)
2. Paratonsillar bulge - ask patient to open wide and say "Aah":
   • A deep lobe PSA pushing through the stylomandibular tunnel presents as a medially displaced tonsil or bulging of the soft palate/lateral pharyngeal wall
   • This is the "dumbbell tumor" - one lobe palpable externally, one palpable intraorally

Minor Salivary Gland PSA (Hard Palate)

• Smooth, firm, dome-shaped submucosal swelling
• Mucosa over it is intact and normal-colored
• Non-tender, non-pulsatile
• Slowly enlarging over months-years

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Step 7: Bimanual Palpation (for Deep Lobe / Parapharyngeal Extension)

• Place one finger intraorally against the tonsil/lateral pharyngeal wall
• Place the other hand externally over the parotid
• A deep lobe extension or dumbbell tumor will be felt compressible between both fingers
• Always examine both sides for comparison

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Step 8: Regional Lymph Node Examination

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Step 9: Examination of Other Salivary Glands

• Contralateral parotid: Usually normal; bilateral parotid swelling is characteristic of Warthin's tumor or systemic disease (sarcoidosis, Sjögren's), not PSA
• Submandibular glands: Bimanually palpate (one finger under chin externally, one finger on floor of mouth intraorally) - PSA can arise here
• Sublingual glands: Inspect and palpate intraorally

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Step 10: Summary - Benign PSA vs. Malignancy Alarm Signs

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Complete Examination Summary (OSCE-Style)

"This patient has a painless, slow-growing, well-defined, firm, mobile, bosselated swelling in the right parotid region measuring approximately [X] cm. The overlying skin is normal and freely mobile. The ear lobe is elevated. There is no facial nerve weakness on formal cranial nerve testing. Intraorally, the right Stensen's duct orifice is producing clear saliva; there is no paratonsillar bulge. Regional lymph nodes are not palpable. These findings are consistent with a pleomorphic adenoma of the right parotid gland."

• Bailey and Love's Short Practice of Surgery 28th Edition, p. 861
• Scott-Brown's Otorhinolaryngology Head & Neck Surgery, p. 162
• Cummings Otolaryngology Head and Neck Surgery, p. 1647

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Clinical Examination of Hydrocele

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Definition

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Types - Anatomical Classification

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Step 1: General Inspection

• Patient examined in both standing and supine positions - mandatory
• Note which side is affected (unilateral or bilateral)
• Assess the overall scrotal appearance before touching

On Inspection

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Step 2: The Three Key Clinical Questions

Question 1: Can you GET ABOVE the swelling?

• Place two fingers at the neck of the scrotum, just below the external inguinal ring
• Attempt to pinch and feel a normal spermatic cord above the upper limit of the swelling

This is the single most important initial distinction in scrotal examination.

Question 2: Is the testis/epididymis separately palpable?

• Attempt to feel the testis and epididymis separately within/around the swelling

Question 3: Does the swelling transilluminate?

• In a dark room, press a torch/penlight firmly against one side of the swelling
• Look from the other side

Hydroceles transilluminate brightly. This is the clinical hallmark of a fluid-filled scrotal swelling.

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Step 3: Palpation

Technique

• Warm hands; hold scrotum gently with non-dominant hand
• Use dominant hand to systematically palpate all scrotal contents
• Compare both sides

Characteristics to Elicit

Testing for Fluctuance

• Place index and middle fingers of one hand on opposite poles of the swelling
• Flick with the other hand - impulse transmitted in all directions = fluctuant = fluid-filled

Testing for Reducibility

• Attempt to compress or reduce the swelling upward
• A hydrocele is NOT reducible (in contrast to a hernia)
• Exception: A congenital/communicating hydrocele may partially reduce when the child lies down (fluid drains back into peritoneal cavity via patent processus)

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Step 4: Special Tests

Transillumination (Confirmatory Test)

1. Darken the room
2. Apply a strong torch/penlight to the posterior surface of the scrotal swelling
3. Observe from in front

Important caveat: A large, tense hydrocele may not transilluminate well if the walls have become thickened. An ultrasound is invaluable in this situation.

Cough Impulse

• Ask patient to cough while you feel the swelling
• Hydrocele: No cough impulse (sac is isolated from peritoneal cavity in acquired type)
• Communicating hydrocele / hernia: Positive cough impulse

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Step 5: Specific Features by Type

Vaginal (Primary) Hydrocele

• Most common type; middle-aged to older men
• Painless, globular, smooth scrotal swelling
• Can get above it
• Testis impalpable (enclosed)
• Positive transillumination
• Non-tender, non-reducible
• May reach large size before patient presents

Congenital (Communicating) Hydrocele

• Infants/young children; history of intermittent or variable swelling
• Swelling may be smaller in the morning (fluid drained back overnight in recumbent position)
• Pressure on swelling may not fully empty it (communication too small)
• Check for bilateral swelling - if bilateral, rule out ascites
• Usually no hernia (communication too small to allow herniation of bowel)

Hydrocele of the Cord

• Oval, smooth swelling above the testis along the cord
• Separate from testis (testis palpable below it)
• Key sign: moves downward and becomes less mobile when the testis is pulled gently downward (the cord tethers it)
• May be mistaken for an inguinal hernia
• Transilluminates brightly

Secondary Hydrocele

• In a young man, an acutely presenting hydrocele raises suspicion of underlying testicular tumor - do NOT aspirate (risk of malignant needle-track implantation)
• May also occur secondary to infection (epididymo-orchitis), trauma, torsion, or post-radiotherapy
• The secondary cause may be detectable on careful palpation (thickened/tender epididymis, irregular testis)

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Step 6: Complete the Examination

Examine Both Sides

• Compare both testes in size, consistency, and position
• Feel for epididymis posterolaterally to each testis

Examine the Inguinal Regions

• Check for evidence of a hernia or lymphadenopathy bilaterally
• Palpate the inguinal canal for any direct or indirect hernia

Examine the Abdomen

• Particularly important in bilateral hydroceles in children (rule out ascites)
• In adults with secondary hydrocele: examine for abdominal lymphadenopathy or retroperitoneal mass (testicular tumor metastasizes to para-aortic nodes)

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Step 7: Investigations

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Step 8: Differential Diagnosis of Scrotal Swelling

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Examination Summary (OSCE-Style)

"This patient has a smooth, globular, non-tender, fluctuant swelling in the right scrotum. The upper border is well-defined and I am able to get above the swelling to feel a normal spermatic cord. The testis and epididymis are not separately palpable within the swelling. There is no cough impulse and the swelling is not reducible. Transillumination is positive - the swelling glows brightly. These findings are consistent with a vaginal hydrocele of the right side. I would confirm this with a scrotal ultrasound and ensure the underlying testis is normal."

• Bailey and Love's Short Practice of Surgery 28th Edition, p. 1586-1587
• General Anatomy and Musculoskeletal System - THIEME Atlas, p. 248