Larynx: Diagnosis and Margins

Larynx: Diagnosis and Margins
Invasive keratinizing squamous cell carcinoma is characterized by irregular nests of atypical squamous epithelium, with focal areas of keratinization, eliciting a loose desmoplastic stromal response.
Verrucous carcinoma invades as a broad, uniform pushing front. This is a difficult pattern of invasion to recognize in small biopsies. Diagnosis should be reserved for completely excised tumors.
SURGICAL/CLINICAL CONSIDERATIONS
Goal of Consultation
  • Determine if malignancy or dysplasia is present
  • Determine if margins are free of carcinoma or dysplasia
Change in Patient Management
  • Carcinoma may be excised or treated with radiation therapy if margins positive
  • Multiple biopsies may be used to map extent of tumor and determine how much tissue to excise
  • Additional tissue may be taken at areas of margin involvement to obtain clear margins
Clinical Setting
  • Smoking and alcohol use are major risk factors for conventional squamous cell carcinoma
  • Patients with advanced carcinoma, airway compromise, or recurrent carcinoma may undergo a total laryngectomy
  • Patients with limited involvement or in situ carcinoma may be treated with a partial laryngectomy
SPECIMEN EVALUATION
Gross
  • Biopsies are often small and fragmented
  • Total laryngectomy
    • Superior mucosal margins are the margins most likely to be positive for carcinoma
      • Anterior/lateral soft tissue margins may be involved if tumor is advanced
    • Separate margins may be submitted as small specimens by surgeon
    • Specimen may contain additional pharyngeal or thyroid tissue
  • Partial laryngectomy
    • Orientation by surgeon may be necessary
    • Separate margins may be submitted as small specimens by surgeon
Frozen Section
  • Small biopsies and separate margins may be completely frozen
  • If mucosa can be identified, specimen should be embedded in a way to allow for vertical sections and assessment of invasion
  • Margins should always be taken perpendicular to actual margin
    • En face margins are not capable of evaluating narrow (1-2 mm) but tumor free margins
      • Distance to margin cannot be determined and may be clinically important
MOST COMMON DIAGNOSES
Keratinizing (Conventional) Squamous Cell Carcinoma
  • Tumor may exhibit differing patterns of invasion
    • Broad pushing front of invasion
      • This pattern is especially challenging in small biopsies and may require presence of adjacent normal tissue to recognize presence of invasion
    • Irregular nests of tumor cells &/or individual infiltrative cells
      • This is a more obvious pattern of invasion and can be recognized in small biopsies
  • Abnormal keratinization, frequent mitoses, necrosis, nuclear pleomorphism and hyperchromasia, &/or a desmoplastic stromal response may be appreciated
Verrucous Carcinoma
  • Extremely well-differentiated variant of squamous cell carcinoma with minimal cytologic atypia
  • Uniform front of invasion with bulbous rete ridges
  • When strictly defined, only poses risk of local recurrence
  • Diagnosis should be reserved for excised tumors, as similar features may be seen in areas of a conventional squamous cell carcinoma
Basaloid Squamous Cell Carcinoma
  • Clinically aggressive variant
  • Basaloid tumor cells with scant cytoplasm and high-grade features including necrosis, nuclear hyperchromasia, and frequent mitoses
  • Histologic recognition as squamous carcinoma relies on identification of squamous differentiation (keratinization or intercellular bridges) or a coexisting component of squamous dysplasia/carcinoma in situ
  • Must be distinguished from oropharyngeal human papillomavirus (HPV)-associated squamous cell carcinoma, which has a favorable prognosis
  • Also must consider other high-grade small round cell malignancies, especially small cell carcinoma
    • Distinction often requires special stains
    • Adequate on frozen section to diagnose as a basaloid carcinoma and defer to permanent sections
Sarcomatoid (Spindle Cell) Carcinoma
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Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Larynx: Diagnosis and Margins

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