DISCUSSION
While the local extension of hypopharyngeal and thyroid tumors to the
larynx is common, metastatic laryngeal involvement remains rare; since
fertile et al. in 1987, a 13 laryngeal metastasis was reported in the
English literature from Colo-rectal cancer, and by Zenga et al. in 2016
colorectal was the most common primary site for laryngeal metastasis
followed by renal and prostate cancer 6 cases each, then 5 cases of skin
melanoma, the remaining cases were secondary to lung, bone, breast,
thyroid, liver and female genital tract cancers. (3)
Trans-glottic glottic involvement was the most common compromising about
40% of the reported cases, followed by supraglottic area, then
subglottic in less than 10% of the true vocal cords were involved,
about 70% of the cases were reported in males, with the median age of
59 years, initial presentation in more than 60% was Dysphonia, the
median time to laryngeal metastasis diagnosis was 3 years. (3)
The treatment modalities for secondary laryngeal metastasis vary
depending on the stage of the disease, the number of the metastatic
focus, and the involvement of other organs; in a case reported by
Therasma et al. in 2008, the laryngeal metastasis was managed with organ
preservation surgery as the patient was in remission from his primary
cancer with no other organ involvement. (7) Another case by Marioni et
al. was managed with total laryngectomy due to extensive laryngeal
involvement, and local control was controlled at the time of laryngeal
diagnosis. (8) Puxeddu et al., Sano et al., and Ta et al. managed their
patients with a tracheostomy to protect the airway from local disease
advancement. (9-11) In other cases, reported the local control of the
disease was achieved by laser excision by Nd-YAG laser and
CO2 Laser. (5, 12) Summary of laryngeal metastasis
secondary to colorectal cancer is summarized in table 1.
Due to unfamiliarity with secondary laryngeal cancers, there is no
census of the treatment guidelines; treatment options depend on the
stage at the time of diagnosis, solitary laryngeal involvement, or the
presence of other metastatic focus; however, it is thought that
laryngeal cancer is still under-reported, as one post-mortem study
reported by Prescher et al. showed laryngeal involvement in 6 autopsies
out of 6 patients with prostate cancer and Horny and Kaiserling found 10
out of 14 patient with hematopoietic malignancy found to have laryngeal
metastasis. (13, 14) Incidental laryngeal metastasis without symptoms is
also evident, as reported by Xia et al. when a PET CT (positron emission
tomography-computed scan) was done for an elevated AFP (Alfa
fetoprotein) showed increased uptake in the larynx. (15)