B. Geissler, T. Wagner, R. Dorn, et al.
ryngeal nerve (6, 7), or a hypocalcaemia due to
pressure on the parathyroid glands were lacking in
our patient. These symptoms are usually reversible
after decompression (3, 10, 11).
steroids confirm our experience. It is speculated
that steroids may be helpful in the initial phase of
the disease, but are without benefit in the end-
stage where there is completely transformed fi-
brotic tissue (9). Nevertheless, a time-limited treat-
ment with steroids should be performed in any pa-
tient (8, 9, 17, 18).
Because of the self-limiting character, only moder-
ate surgical management should be chosen to re-
lieve tracheal obstruction. A more extensive dis-
section increases the risk of damage to vital neck
structures because of the altered anatomy caused
by the fibrosclerosis (3, 5). Riedel’s recommenda-
tion of a wedge-resection of the thyroidal isthmus
is still preferred (3, 5, 15). This results in a release of
tracheal compression. Simultaneously, an obliga-
tory thyroid biopsy is obtained to confirm the di-
agnosis and to exclude carcinoma (15, 20). The pre-
sented patient showed an extensive abscess ex-
tending to the upper mediastinum. Therefore, a sin-
gle wedge excision would not be sufficient. That
was the reason to change the strategy from a min-
imal-invasive surgery normally performed in this dis-
ease to a hemithyroidectomy.
Riedel already theorized the accompaniment of
endarteritis in his thyroiditis. Soon after, a detailed
description of the vascular changes showed a dif-
fuse infiltration of lymphocytes and plasma cells in
the walls of small and medium-sized vessels (4, 21,
22). Meijer et al. reported five cases with inflam-
matory changes of small and large veins in the in-
filtrative, occlusive, and sclerosing stages. They con-
sidered this to represent an occlusive phlebitis,
which could not be found in other thyroid diseases
like Hashimoto or granulomatous thyroiditis “de
Quervain”. Therefore, an occlusive phlebitis was
postulated as a diagnostic feature of Riedel’s thy-
roiditis (22).
We postulate, that in our case inflammatory infil-
tration of the arteries leads to vessel occlusion with
ischemia, infarction and subsequent formation of a
sterile abscess. This supports Riedel’s theory of an
endarteriitis and favours the pathogenetical role of
occlusive vasculitis.
Clinical diagnosis of Riedel’s thyroiditis is difficult.
Besides physical examination findings of sonogra-
phy, scintigraphy and even magnetic-resonance
scan may be normal or mimic carcinoma (5, 9). The
disease is characterized by a chronic inflammation
but laboratory findings are non-specific (3, 8).
However, as in our patient, increased inflammato-
ry parameters are possible (3, 8). These were due to
the systemic reaction to infarcted and necrotic thy-
roid tissue. Antithyroid antibodies were absent. In
literature antibodies are found in 45 to 67% (4, 5),
but it is not clear whether these are pathogenic or
a phenomenon as a result of exposure of seque-
stered antigens to the immune system through tis-
sue damage (4, 9). The diagnosis usually requires
histologic verification (7). Samples received by nee-
dle biopsy are not diagnostic because the fibrotic
reaction surrounding an undifferentiated carcino-
ma may be confused with the fibrotic reaction seen
in Riedel’s thyroiditis (3, 5, 12, 13). Though in our
case a punch biopsy already hinted at the correct
diagnosis, an open biopsy is always essential.
The main differential diagnosis of Riedel’s thyroidi-
tis is carcinoma, with same clinical features like dys-
phonia, stridor, and unilateral hard swelling of the
thyroid gland (14). Besides carcinoma other enti-
ties of thyroiditis must be included in the differen-
tial considerations like chronic lymphocytic thy-
roiditis (Hashimoto’s disease) or subacute thyroidi-
tis de Quervain (5, 8). The acute suppurative thy-
roiditis is a very rare form of inflammation of the
thyroid gland caused most often by hematogenic
spread of bacteria, fungi or parasites (5). Besides
the local inflammatory signs, the diagnosis would
be based on fever, increased inflammatory para-
meters and the bacteriologic proof. In our case, the
microbiologic examinations confirmed that the
evacuated fluid was sterile. The abscess was most
likely caused by vessel occlusion but not infection.
Riedel’s thyroiditis is self-limiting with a favorable
prognosis (15). If the disorder is confined to the
neck, complications are rare and include airway
compression, hypothyroidism, and hypoparathy-
roidism (3, 5, 16).
CONCLUSIONS
The pathophysiology of Riedel’s thyroiditis is most
likely caused by an occlusive vasculitis. Surgical pro-
cedures depend on the extension of symptoms and
inflammation. While simple wedge resection can re-
lieve tracheal obstruction in chronic disease without
risk to the parathyroids and the laryngeal nerve, ex-
tended inflammation and necrosis requires advanced
surgical interventions, like hemithyroidectomy.
A dramatic improvement has been demonstrated
by systemic use of high-dose glucocorticoid even
with recovery of parathyroid and vocal cord func-
tion (3, 4, 8, 9, 17-19). This and the finding of anti-
thyroid antibodies in up to 67% of 178 reviewed
patients support the hypothesis of an autoimmune
reaction (3, 4). Other reports of no response to
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