Hypopharyngeal squamous cell carcinoma (SCC) is the most common malignant tumor of the hypopharynx and constitutes approximately 5-10% of head and neck SCCs. The piriform sinus is the most commonly affected site (60-70%), followed by the posterior pharyngeal wall and postcricoid region. Due to late symptom onset, it is usually advanced at diagnosis (Stage III-IV). CT and MRI show an asymmetric soft tissue mass in the piriform sinus, heterogeneous enhancement, central necrosis, and invasive margins. Prevertebral fascia invasion, laryngeal cartilage invasion (especially cricoid), and cervical LAP must be evaluated. Smoking and alcohol use are the most important risk factors; Plummer-Vinson syndrome is a predisposing factor for postcricoid SCC.
Age Range
50-80
Peak Age
65
Gender
Male predominant
Prevalence
Uncommon
Hypopharyngeal SCC results from malignant transformation of squamous epithelium of the pharyngeal mucosa. Chronic carcinogen exposure (smoking, alcohol) leads to the progression of mucosal dysplasia → carcinoma in situ → invasive carcinoma. The frequent involvement of the piriform sinus relates to its anatomical structure — the piriform sinus is a deep recess lateral to the laryngeal vestibule where secretions and food debris accumulate, causing chronic mucosal irritation. The tumor tends to spread submucosally — therefore even if the superficial lesion appears small, deep invasion may be extensive. The medial wall of the piriform sinus is in contact with the aryepiglottic fold — medial spread means invasion of the larynx. The lateral wall is adjacent to the inner surface of the thyroid cartilage — lateral invasion leads to cartilage destruction. The apex is at the cricoid cartilage level — apical tumors with cricoid invasion limit surgical options. Due to rich lymphatic drainage, cervical LAP is present at diagnosis in 60-70% of cases. Prevertebral fascia invasion may constitute a contraindication for surgery.
Obliteration of the normal air column of the piriform sinus by a soft tissue mass on CT is the most characteristic finding of hypopharyngeal SCC. Normally, bilateral piriform sinuses show symmetric air columns — asymmetric obliteration should always suggest tumor.
Contrast-enhanced CT shows a heterogeneously enhancing asymmetric soft tissue mass in the piriform sinus. The mass partially or completely obliterates the normal air column of the piriform sinus. Central necrotic areas are low density creating the heterogeneous enhancement pattern. Mass margins are invasive/irregular and extension to adjacent structures must be evaluated: medial — aryepiglottic fold and larynx, lateral — thyroid cartilage, inferior — cricoid cartilage and esophageal inlet, posterior — prevertebral muscles and fascia.
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A heterogeneously enhancing soft tissue mass obliterating the normal air column is noted in the left piriform sinus; consistent with hypopharyngeal SCC.
Cricoid and thyroid cartilage invasion is seen on CT as cartilage sclerosis (early finding), erosion, or complete destruction. Cricoid cartilage invasion is particularly critical because it makes partial laryngeal surgery impossible and requires total laryngopharyngectomy. Arytenoid cartilage invasion is associated with vocal cord fixation. Extralaryngeal soft tissue extension of the tumor is evaluated from the cartilage destruction site.
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Erosion/destruction due to tumor invasion is noted in the posterior lamina of the left cricoid cartilage; this finding strengthens the indication for total laryngopharyngectomy.
Hypopharyngeal SCC shows diffusion restriction on DWI but less marked than lymphoma. ADC values are typically between 0.8-1.2×10⁻³ mm²/s. Due to MRI's superiority in cartilage invasion assessment, DWI should be evaluated together with T2 and contrast-enhanced sequences.
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The hypopharyngeal mass shows diffusion restriction on DWI with an ADC value of ... ×10⁻³ mm²/s.
Cartilage invasion is evaluated on MRI T2-weighted sequences. Normal cartilage medulla is hyperintense on T1 due to fat signal; tumor invasion disrupts this fat signal creating low T1 and increased T2 signal change. On T2, normal cartilage cortex appears as a thin low-signal line — disruption of this line indicates invasion.
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On MRI T2-weighted sequences, disruption of the inner cortex and medullary signal change in the left thyroid cartilage is noted, consistent with cartilage invasion.
FDG-PET/CT shows intense FDG uptake in the primary hypopharyngeal mass. Uptake is decreased/absent in central necrotic areas (differs from lymphoma). Cervical metastatic LAPs are also FDG avid. PET-CT is used for distant metastasis screening, synchronous second primary tumor detection, and treatment response assessment.
Report Sentence
The left piriform sinus mass shows intense uptake on FDG-PET (SUVmax: ...); photopenic areas corresponding to central necrosis are present.
Criteria
Most common location (60-70%)
Distinct Features
Laryngeal invasion common, cricoid apical involvement critical for surgical planning
Criteria
Second most common, flat plaque-like mass
Distinct Features
Prevertebral fascia invasion early; longitudinal spread common
Criteria
Rarest, more common in women, Plummer-Vinson associated
Distinct Features
Early esophageal invasion, circumferential growth, total laryngopharyngectomy often required
Distinguishing Feature
Lymphoma homogeneous, minimal necrosis, oropharyngeal; SCC heterogeneous, necrosis common, hypopharyngeal
Distinguishing Feature
Zenker posterior diverticulum containing air/fluid, no enhancement; SCC solid mass, heterogeneous enhancement
Distinguishing Feature
Retention cyst smooth-bordered cystic, no enhancement; SCC solid/mixed, invasive, enhancement present
Urgency
urgentManagement
surgicalBiopsy
NeededFollow-up
specialist-referralHypopharyngeal SCC requires multidisciplinary tumor board evaluation (ENT, radiation oncology, medical oncology, radiology). Early stage (T1-T2): transoral laser surgery or radiotherapy; advanced stage (T3-T4): chemoradiation or surgery (partial/total laryngopharyngectomy) + adjuvant therapy. 5-year survival is 30-35% (all stages).
Hypopharyngeal SCC has one of the worst prognoses among head and neck carcinomas. Due to late diagnosis, high nodal metastasis rate, and frequently advanced-stage presentation, 5-year survival is 30-35%. Early stage: surgery or radiotherapy; advanced stage: chemoradiation or total laryngopharyngectomy.