Metastasis of thyroid carcinoma to the buccal mucosa
Metastatic tumors to the oral cavity are uncommon,
contributing approximately 1% of all oral malignant neoplasms,
which occur either in the jaws (mostly located in
the mandibular molar area), or even more infrequently in
the oral soft tissues (<0.1% of all oral malignancies).
Nearly any malignant neoplasm can metastasize to the
oral cavity.
The most frequent locations of primary cancers
with metastases to the oral cavity in males are the lung,
kidney, liver, and prostate, whereas those in females are
the breast, genital organs, kidney, and colo-rectum.
To our knowledge, oral metastasis from the thyroid is very uncommon.
Hereby, we reported a rare case of follicular
thyroid carcinoma with metastasis to the buccal mucosa.
A 78-year-old woman visiting the oral and maxillofacial
department of our institution complained of painful ulceration
over the right buccal mucosa for about one month.
Intraoral examination revealed a tender, painful ulcerative
lesion measuring about 1.0 cm in diameter over the right
buccal mucosa (Fig. 1A).
The patient had a history of diabetic
Mellitus and hypertension.
Moreover, she has suffered
from follicular thyroid carcinoma with multiple distant
metastases to the left humerus and lung one year ago.
So, a clinical impression of oral metastatic cancer was suspected.
An incisional biopsy was performed subsequently.
Microscopically, the tissue sections showed a neoplasm with the
tumor cells arranged in a follicular pattern with colloid
substances in the follicular lumens (Fig. 1B and C).
The tumor cells also revealed nuclear hyperchromatism and
pleomorphism (Fig. 1C).
Immunohistochemically, the
neoplastic cells were positive for CK7 (Fig. 1D),
thyroid transcription factor-1 (TTF-1) (Fig. 1E), thyroglobulin
(Fig. 1F), and hector battifora mesothelial antigen-1
(HBME-1) (Fig. 1G), and focal weakly positive to galectin-3
(Fig. 1H). Additionally, the histopathological features of
the oral soft tissue metastatic lesion were compatible with
those of primary follicular thyroid carcinoma (Fig. 1I).
So, metastatic thyroid follicular carcinoma to the right buccal
mucosa was rendered. Due to the old age, the poor systemic
conditions, and multiple distant metastases of the patient,
the patient herself and the family determined not to undergo
further radical treatment.
Cancer metastases to the oral soft tissues are mainly
from lung, kidney, skin, and breast in females.2 Reviewing
the English literature, metastasis to the oral mucosa from
the thyroid is very rare with only three cases having detailed
descriptions of the lesions in the literature.
3e5 Whittaker et al. reported a case of follicular thyroid carcinoma with
metastases simultaneously to the dorsal tongue and lower
lip in an 87-year-old man.
3 Piattelli et al. presented a
gingival metastasis from a medullary thyroid carcinoma in a
54-year-old female,4 whilst Siddique et al. documented
another case of gingival metastasis from papillary thyroid
carcinoma in a 71-year-old man.
5 Therefore, the current
case, to the best of our knowledge, maybe the fourth case
of metastatic oral soft tissue lesion from thyroid and also
the first reported case in the buccal mucosa.
