5- DISCUSSION
We presented an extremely rare case of a LCS with cervical LNMPTC. To
our best knowledge, this is the first case reported in literature, where
these two malignancies coexist. In 2012 Buda et al 22,
reported one case of a LCS arising from cricoid cartilage associated to
a PTC. Vahidi et al 23 reported a case of a LCS
arising from thyroid cartilage with an incidental PTC. Lymph node
metastasis was absent in both reports.
As mentioned before, LCS are rare tumors, which often require surgical
treatment. The key in order to choose the appropriate treatment is to
balance the oncological with the functional outcomes. The goal in these
patients should be to remove the tumor with adequate margins avoiding
local recurrences or distant metastasis, trying to preserve the voice
and normal swallow. For this reason, surgeons have described different
surgical techniques, including minimally invasive local resections,
laser procedures, hemicricoidectomy, partial laryngectomies with
reconstruction or not, and more aggressive techniques like total
laryngectomy. Theoretically, less aggressive techniques are indicated
for low-grade and not extensive tumors, and total laryngectomy is the
choice for high-grade, extensive tumors and recurrences. In our case we
decided to perform total laryngectomy, given the extension of the lesion24,25. In our systematic review, laryngectomy (total
or partial) was the treatment of choice in most of the patients,
followed by local excision or laser removal of the tumor. Survival
appeared to be lower in those patients treated with total laryngectomy,
and this may have an explanation, probably because those candidates to
this surgical technique might have more advanced tumors.
Cervical metastases of CS are rare, and neck dissection should be
performed only if radiological or clinical evidence of disease is
present. In our case, neck imaging revealed pathological nodes, so
bilateral neck dissection was performed. Besides, due to tumor size and
location, total thyroidectomy was performed. Treatment of PTC is
debatable. Some authors advocate for active surveillance in cases of
thyroid microcarcinoma or occult PTC 26. In
other cases, based upon different risk factors, a thyroid lobectomy or
total thyroidectomy can be the option 18. Different
authors described the appearance of incidental metastatic PTC in neck
dissections of non-thyroidal surgery, with a prevalence up to near 2%27. Thyroid carcinoma in cervical lymph nodes can have
two possible origins. First, the possibility of malignant transformation
of ectopic or heterotopic thyroid tissue. This fact can be explained due
to anomalies in the migration of the thyroglossal during embryologic
development. Also, alterations in development of the pharyngeal pouch
endoderm can explain the presence of ectopic tissue in cervical lymph
nodes 28. Although ectopic thyroid malignancies
commonly appear together with tumoral native tissue, in some cases a
benign thyroid gland was found with ectopic PTC in different upper body
locations including the neck 29. Second, the
appearance of PTC lymph node metastasis from thyroid is not unfrequent
in patients with thyroidal cancers as reported by So et al. in up to
90% of the cases 30. This fact is associated with
locoregional recurrence and a poor prognosis. In our systematic review,
few cases reported cervical metastasis of CS 31-33. In
none of them PTC lymph node metastasis was found.
Comparing our systematic review with the biggest series previously
published 3,12, in general, our results are in
agreement, regarding tumor grading, anatomical site, tumor size,
treatment modality, symptomatology and follow-up with them.
Thus, LCS are more common in men, affect people in their sixties, the
main symptoms are dyspnea and hoarseness, CT scan is the most common
imaging technique for diagnosis, cricoid cartilage is the most frequent
location, total laryngectomy is the most commonly used surgical
technique, well-differentiated CS is the most frequent histopathologic
finding, distant metastases are rare and survival is related to
histologic differentiation, anatomical involvement, surgical technique
and recurrence.
The main limitation for this systematic review was the heterogeneity in
data reporting, primary and secondary outcomes and follow-up. The search
included articles from 1968 to 2020, and clinical information in
different series were unavailable or inaccurate. This fact made that
some series, had to be excluded from our systematic review34-40 despite the high number of cases reported.
In conclusion, with this systematic review we provide a reliable general
view of different aspects of LCS. These tumors are rare, and generally
with a better prognosis than other laryngeal tumors. We also presented
an extremely rare case of coexistence of LCS and cervical LNPTC. This is
the first case reported in literature where this 2 entities appear
simultaneously in a patient.