Download Full Text - J

Neurol Med Chir (Tokyo) 45, 205¿208, 2005
Skull Metastasis From Thyroid Follicular Carcinoma With
Difficult Diagnosis of the Primary Lesion
—Case Report—
Ismail AKDEMIR, Fatih S. EROL, Nusret AKPOLAT*, M. Faik OZVEREN,
Murat AKFIRAT**, and Seyfettin YAHSI*
Departments of Neurosurgery, *Pathology, and **Radiology,
Firat University School of Medicine, Elazig, Turkey
Abstract
A 57-year-old male patient presented with an immobile ellipsoid mass of 6-cm diameter in the right
occipitoparietal region. Cranial computed tomography showed the mass with dense contrast enhancement causing bone destruction. After embolization of the mass, total resection was performed. Histological examination showed the mass had a capsule, with no invasion of the dura mater or dermis, and the
follicles of various sizes covered with mono-lined thyrocytes were full of colloid. Immunohistochemical
examination showed positive staining for thyroglobulin. Postoperatively, levels of thyroid hormones
were normal, and thyroid ultrasonography and technetium-99m scintigraphy showed no abnormalities.
Fine needle aspiration biopsy performed at various locations of the thyroid gland revealed no atypical
thyroid cells. Whole body technetium-99m scintigraphy found no abnormal bone involvement. The
histological evidence was suggestive of follicular carcinoma metastasis. Surgical treatment was
planned for the thyroid gland, but the patient did not consent. Two years later, the patient presented
with the pain and sensitivity in the sacrum, the right iliac wing, and the right caput femoris. Computed
tomography revealed lytic lesions in these areas. Bone metastases were identified. Whole body
scintigraphy showed increased activity in these regions, but the cranium and all other tissues were
normal. The patient underwent total thyroidectomy under a diagnosis of follicular carcinoma. The
present case of a lytic skull lesion associated with normal thyroid tissue on admission but finally
treated as follicular thyroid cancer emphasizes the difficulty in histological discrimination of follicular
carcinoma from normal thyroid tissue.
Key words:
cranium,
follicular carcinoma,
metastasis
Introduction
Here we discuss a case of skull metastasis from
thyroid follicular carcinoma which was difficult to
identify.
Skull metastases originating from tumors of the
organs are rare. The most common forms are pulmonary and breast cancer metastases and prostate
carcinomas.2,6) Bone metastasis of thyroid carcinoma is the second most common form of metastasis
following pulmonary metastasis.1–3) However,
metastases in the skull associated with carcinoma
of the thyroid are rare, accounting for only 2.5% to
5.8% of cases. Solid masses causing lytic lesions in
the cranium are suggestive of metastasis and present
as various radiological findings with osteoblastic
activity.4,6,7) The differential diagnosis of such
lesions is essential for follow up and treatment.
Received
April 1, 2004;
Accepted
Case Report
A 57-year-old male patient was referred to the
Department of Neurosurgery, Firat University
School of Medicine, with headache and a mass in
the right occipitoparietal region. The mass had
formed in the last year and rapidly grown within 2
months. Systemic and neurological examinations
found no abnormalities except an immobile ellipsoid
mass, 6 cm in diameter, in the occipitoparietal
region.
Computed tomography (CT) revealed a semisolid
mass with contrast enhancement causing bone de-
October 25, 2004
205
206
I. Akdemir et al.
Fig. 1
Axial cranial computed tomography scan
showing dense contrast enhancement of the
mass causing bone destruction in the right
occipitoparietal region.
Fig. 2
Axial T2-weighted magnetic resonance
image showing no invasion of the scalp and
dura mater owing to the well-circumscribed
capsule of the mass in the occipitoparietal
region.
struction in the right occipitoparietal region (Fig. 1).
Magnetic resonance imaging showed absence of
dura mater and scalp invasion of the richly vascular
mass (Fig. 2). Digital subtraction angiography (DSA)
showed the mass was supplied by the right occipital
(75%), left occipital (20%), and right meningeal
arteries (5%) (Fig. 3A), and drained through the
Fig. 3
Preoperative digital subtraction angiograms
showing the main blood supply through the
occipital artery (A) and no venous connection of the mass with the superior sagittal
sinus (B), and obstruction of the blood
supply by embolization 3 days later (C).
scalp veins, not through the sinuses (Fig. 3B). After
DSA had confirmed embolization, the mass was
totally resected (Figs. 3C and 4). The eroded bone
Neurol Med Chir (Tokyo) 45, April, 2005
Thyroid Metastasis to the Skull
Fig. 4
207
Photograph showing the mass after total
removal, which was round, semi-solid, and
6 cm in diameter.
parts were removed until normal bone structures
were exposed.
Histological examination showed the mass had a
capsule, with no invasion of the dura mater or
dermis, and the follicles of various sizes covered
with mono-lined thyrocytes were full of colloid
(Fig. 5B). Immunohistochemical staining showed
diffuse positive staining for thyroglobulin (Fig. 5A).
Postoperatively, his levels of thyroid hormones
were normal. Thyroid ultrasonography and technetium-99m scintigraphy also showed no abnormalities. Fine needle aspiration cytology of various parts
of thyroid gland revealed no atypical thyroid cells.
Whole body technetium-99m scintigraphy showed
no bone involvement. Hormone and physical
examinations detected no abnormalities in the
postoperative 3rd and 6th months. Physical examination of the cranium also found no abnormalities.
Histological examination of the mass suggested
follicular carcinoma metastasis, so surgical treatment of the thyroid gland was planned. However,
the patient did not consent to the operation.
Two years after the operation, the patient presented to our clinic with pain and sensitivity over the
sacrum, the right iliac wing, and the right caput
femoris. CT showed lytic lesions in these regions.
Whole body scintigraphy showed increased activity
in these regions, but the cranium treated before and
other bone structures were normal. The patient
underwent total thyroidectomy under a diagnosis of
follicular carcinoma. Local radiotherapy was performed for the metastases. Follow-up examination
after 1 year detected no recurrence.
Neurol Med Chir (Tokyo) 45, April, 2005
Fig. 5
Photomicrographs revealing normal thyroid
follicles of varying sizes filled with colloid,
and positive immunohistochemical staining
for thyroglobulin (A: ×200), and the cells
well-restricted by the capsule, with no invasion of the dermis or the dura mater, and no
malignant cytological features (B: HE stain,
×40).
Discussion
The largest series of skull metastases from thyroid
carcinomas consists of 12 cases.3) The tumors
caused only osteolytic lesions and formed soft but
not painful hemispheric masses in the cranium.
Most masses causing lytic lesions in various locations are follicular carcinomas, which are vascular
tumors with strong arterial pulsations, and regular
and solid margins.1,3) Generally, the margins of
metastatic masses are irregular. Multiple bone destruction and secondary thickness occur. In our
case, the tumor was a solid, regular, and vascular
formation which caused an extensive bone defect in
the parietooccipital region. The mean age of the patients is 60 years. The incidence is higher in females than in males. The incidence of metastases,
208
I. Akdemir et al.
other than thyroid metastases, significantly increases over 40 years of age with an equal ratio of
males and females.7)
Metastatic tumors with unidentified primary
tumor histology have been reported in patients with
normal thyroid glands.1,3) Follicular carcinoma cannot be discriminated from normal thyroid tissue
based on morphological criteria, so the diagnosis of
carcinoma can be established only in the presence of
a capsule or vessel invasion. Fine needle aspiration
cytology can sample the cells but not the capsule or
the vessels. Therefore, thyroid tumor tissue containing follicular cells is difficult to identify because of
the normal appearance. The changes in the thyroid
gland and hormone profile or histological studies of
cross-sections obtained at thyroidectomy may help
to identify the tumor. Increased scintigraphic
activity is important evidence for both thyroid tissue
carcinomas and metastases.
Distant organ lesions characterized as ectopic
thyroid tissue include cases with either normal
tissue or carcinoma.5) Investigation of follicular
carcinoma at embryologically impossible locations
for ectopic thyroid tissue may provide more specific
findings.
Palpable lytic tumor of the scalp is the principal
physical manifestation, whereas cranial nerve
dysfunction, focal brain symptoms, or symptoms
due to increased intracranial pressure are rare.
However, the most important problem is the bone
defects requiring extensive bone resection.
The mean period until the diagnosis of thyroid
tumors in patients undergoing thyroidectomy is 14.5
years, and until detection of the skull metastasis is
23.3 years.3) However, the mean period until diagnosis of the definite metastatic focus ranges from
5 months to 4 years.3) In our case, the period until
diagnosis of the definite metastatic focus was 2
years. Despite slow progression, the masses can
adopt a variable and insidious clinical profile. In
this period, the clinical profile may be masked a little
longer since no changes may take place in the
thyroid gland and hormone. Strikingly, in our case,
the metastasis involved a different bone focus within
1 year, although there was no recurrence in the first
focus.
The optimum therapy for patients with bone
metastasis due to thyroid tissue tumors involves
complete excision of the thyroid gland together with
all the probable metastatic foci and regional lymph
nodes, and application of local radiotherapy.3) Frequent follow-up examination is also recommended.
The primary focus of thyroid metastasis, which
causes large bone defects, is difficult to define.2,5)
Various reports describe 3 or 4 years of treatment
and follow up for these cases.2,3) These tumors are
rare, difficult to define histologically, and may often
mimic other bone pathologies, so critical clinical
diagnosis and aggressive therapy are required.
References
1)
2)
3)
4)
5)
6)
7)
Inci S, Akbay A, Bertan V, Gedikoglu G, Onol B:
Solitary skull metastasis from occult thyroid carcinoma. J Neurosurg Sci 38: 63–66, 1994
McCormack KR: Bone metastases from thyroid
carcinoma. Cancer 19: 181–184, 1966
Nagamine Y, Suzuki J, Katakura R, Yoshimoto T,
Matoba N, Takaya K: Skull metastasis of thyroid carcinoma study of 12 cases. J Neurosurg 63: 526–531, 1985
Osborn AG: Brain tumors and tumorlike processes, in:
Diagnostic Neuroradiology. St Louis, Mosby, 1994, pp
516–517
Ruchti C, Balli-Antunes M, Gerber HA: Follicular
tumor in the sellar region without primary cancer of
the thyroid. Heterotopic carcinoma? Am J Clin Pathol
87: 776–780, 1987
Turner O, German WJ: Metastases in the skull from
carcinoma of the thyroid. Surgery 9: 403–414, 1941
Wilkins RH, Rengachary SS: Tumors of the skull, in:
Neurosurgery, ed 2. New York, McGraw-Hill, 1996, pp
1503–1529
Address reprint requests to: I. Akdemir, M.D., Neurosurgery Department, Arastirma Hospital, Firat University School of Medicine, 23100 Elazig, Turkey.
e-mail: akdemir23＠yahoo.com
Neurol Med Chir (Tokyo) 45, April, 2005