What Is the Pyriform Sinus and Its Anatomic Boundaries?
The pyriform sinus is one of the vital parts of the hypopharynx (the lowermost part of the pharynx). The pyriform sinus is positioned with the base above and its apex below and is cone-shaped. Superior to the sinus, it becomes limited or is bounded by the pharyngoepiglottic fold. There are two walls to the pyriform sinus: a lateral wall and a medial wall, both of which fuse at the apex region of the sinus. While the upper portion of the sinus has a membranous consistency, the lower part of the pyriform sinus is cartilaginous (as they are formed by the arytenoid and cricoid cartilage medially and by the lamina of the thyroid laterally).
What Are the Boundaries of the Hypopharynx?
The pyriform sinus is part of the laryngopharynx or hypopharynx, the lowermost portion of the pharynx that extends mainly from the hyoid bone level to the lower border of the cricoid cartilage. The hypopharynx region is situated opposite the third to sixth cervical vertebrae. The pyriform sinus possesses a rich lymphatic supply and nerve supply. The lymphatics of this sinus eventually drain into the paratracheal and paraesophageal lymph nodes. The membranous or upper part of the piriform sinus is supplied by the internal laryngeal nerve and the lower or cartilaginous part receives blood supply from the recurrent laryngeal nerve.
What Is Cancer of the Pyriform Sinus?
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This cancer is metastatic meaning it is a malignant tumor that spreads through lymphatic and nerve supply.
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The medial wall of the piriform sinus is most affected by these cancers. The medial wall cancer involvement of this sinus also causes the possibility of bilateral metastasis.
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Predominantly, males are more affected compared to females, and the incidence of this cancer is usually increased in the sixth to seventh decades of life.
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The main associated risk factors for the development of pyriform cancer are smoking and chronic alcoholism. Also, patients suffering from Plummer-Vinson syndrome or the Brown-Paterson Kelly syndrome (characterized by a triad of iron deficiency anemia, esophageal webs, and dysphagia or difficulty swallowing) are considered predisposed to developing further cancers associated with the postcricoid region, as well as tongue cancer and pyriform cancer.
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Research also indicates that people who belong to lower socioeconomic status and are in a state of malnourishment are at increased risk or predisposed to long-term malnutrition, thus developing this cancer.
Does Aggressive Pyriform Cancer Cause Referred Otalgia?
In individuals affected by pyriform sinus cancers, there is a potential for ipsilateral ear (only one side commonly affected), which leads to a condition known as ‘referred otalgia’. In this condition, the central nervous system is unable to differentiate or exactly distinguish the pain source due to the sensory pathway convergence that occurs between the cranial nerves and the nerve supply to the ear. In referred otalgia, the person experiences pain without knowing the exact location, as in ‘referred pain’ via the vagus nerve (tenth cranial nerve).
What Are the Clinical Features of Aggressive Pyriform Cancer?
The earliest symptoms of pyriform cancer that need to be assessed by the otolaryngologist, dentist, maxillofacial surgeon, or physician include the following:
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A vague sensation of sore throat
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Foreign body sensation in the throat region.
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Voice hoarseness (voice gets affected when cancer invades the recurrent laryngeal nerve, the cricoarytenoid joint, or invades further into the paraglottic spaces).
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Dysphagia or difficulty swallowing remains the most common symptom in more than three-fourths of the cases as per documented evidence. The dysphagia symptom becomes more progressive over time. In case history elicited by the dental or the maxillofacial surgeon, patients may often complain of pain of unknown origin from the ear or the jaw region and also of progressive dysphagia that starts with solids and later on as cancer progresses. Liquids may also be difficult to intake.
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Otalgia or referred ear pain is an advanced cancer lesion of the sinus based upon the extent of involvement or spread. Patients also complain of dyspnea, which can be attributed when cancer invades the paraglottic spaces and also when the larynx or voice box becomes edematous or inflamed.
How Is Aggressive Pyriform Cancer Diagnosed?
The investigation that must be carried out in suspected cases of pyriform cancer is as follows:
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CT (Computed Tomography) Or MRI (Magnetic Resonance Imaging) Of the Neck With or Without Contrast: It reveals the extent of tumor growth.
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X-Ray or CT Scan of the Chest: To see for secondary metastatic observation or any associated lung diseases.
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PET (Positron Emission Tomography)-CT Scan: It is done when the surgeon suspects metastasis into the lung, liver, or brain tissues.
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Barium Swallow Test: It is performed when a doctor suspects esophageal growth as a result of progressive cancer.
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Biopsy: It is recommended in affected individuals and conducted on the suspected tissue or site of the lesion, especially for detecting squamous cell carcinoma lesions (that constitute 95 percent of pyriform cancers).
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Other Laboratory Tests: These include hemograms, renal function tests, pulmonary function tests, and liver function tests that are also recommended if needed to assess the metastatic spread and involvement.
What Is the Management of Aggressive Pyriform Cancer?
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Treatment mainly depends upon the tumor spread or extent. The metastatic tissues or organs involved in the case of distant metastasis may also depend on other comorbid conditions present in the affected individuals, such as diabetes, hypertension, kidney disease, chronic obstructive pulmonary disease (COPD), or liver diseases (cirrhosis).
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For early involved tumor lesions in T1 and T2 stages, conservative surgery through transoral approaches or open approaches like laser resection, partial laryngectomy, or partial pharyngolaryngectomy would be advised by the surgeon. In some cases, neck dissection may also be advised in combination in most affected cases.
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Radiation therapy for lymphatic spread control is also considered a beneficial treatment strategy despite surgical resection of the tumor. Oral and dental hygiene also plays an important role that should be assessed by the dentist before starting radiation therapy.
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In advanced lesions of T3 and T4 stages, radical surgery with open approach methods, such as total laryngectomy with partial laryngectomy or total laryngectomy with total laryngectomy may be performed, which proves life-saving in severe stage lesions.
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Ipsilateral or bilateral neck dissection is also combined with such advanced surgical strategies and the patient hence will require reconstruction surgery of the pharynx to ensure the food channel continuity post-surgery.
Conclusion:
Pyriform cancer has the potential for distant metastasis from the neck region to multi organ systems and needs to be immediately intervened by the surgeon for a long-term prognosis. In advanced cases, a person may require pharynx reconstruction surgery to ensure the continuity of the food pipe channel.
