Mastoid recurrence after radiotherapy for nasopharyngeal carcinoma

CASE REPORT
Russell B. Smith, MD, Section Editor
MASTOID RECURRENCE AFTER RADIOTHERAPY FOR
NASOPHARYNGEAL CARCINOMA: TWO CASE STUDIES
Ximei Zhang, MD, Jingwei Luo, MD, Li Gao, MD, Guozhen Xu, MD
Department of Radiation Oncology, Cancer Hospital, Chinese Academy of Medical Sciences (CAMS) and Peking
Union Medical College (PUMC), Beijing, People’s Republic of China. E-mail: nqluo@yahoo.com.cn
Accepted 14 January 2010
Published online 31 March 2010 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/hed.21391
Abstract: Background. The mastoid is a rare site of nasopharyngeal
carcinoma recurrence after radiotherapy, and no
relevant reports are currently in the literature.
Methods. Two case reports are presented describing
patients with a history of nasopharyngeal carcinoma who
received primary radical radiotherapy. The first was treated by
conventional radiotherapy, using 2-dimensional techniques,
while the second was delivered by intensity-modulated radiation
therapy (IMRT).
Results. The patients presented with progressive mastoid
recurrence after radiotherapy at 12 and 16 months, respectively.
Clinical presentation of mastoid recurrence was similar
to mastoiditis. Meanwhile, distant metastasis occurred in both
cases. To date, 1 has died of distant metastasis, and the other
is alive with disease stabilization following chemotherapy
treatment.
Conclusion. This is the first report of mastoid recurrence after
radiotherapy for nasopharyngeal carcinoma, which should
alert clinicians to probe into the pathogenesis and pay attention
to the relationship between mastoid recurrence and distant
metastasis. VC 2010 Wiley Periodicals, Inc. Head Neck 33:
1535–1538, 2011
Keywords: nasopharyngeal carcinoma; recurrence; mastoid;
radiotherapy; prognosis
Nasopharyngeal carcinoma (NPC) is a common tumor
among Chinese people. Radiotherapy is the main
treatment administered for almost all NPC cases. Despite
the fact that radical radiotherapy achieves a 5-
year overall survival rate of more than 70%, 1,2 local
failure remains the major problem for patients with
advanced stages treated by conventional radiotherapy.
Local recurrences after conventional radiotherapy
for NPC are commonly located in the tissues
within the irradiation field, such as ethmoid sinus
and clivus; it is believed that local recurrences might
be related to low dose delivery there and inappropriate
radiation field. 1 Thus far, no mastoid recurrences
have been detailed in the clinical literature.
Correspondence to: Jingwei Luo, MD
VC
2010 Wiley Periodicals, Inc.
CASE REPORT
Case 1. A 45-year-old man was admitted to
our hospital with complaints of decreased hearing
in the left ear for 4 months and epistaxis for
half a month. Nasopharyngeal biopsy rendered
the diagnosis of poorly differentiated squamous
cell carcinoma. An MRI scan demonstrated a
well-circumscribed mass in the left lateral wall
extending into the ipsilateral parapharyngeal
space and an enlargement of the bilateral cervical
nodes (Figure 1). Further clinical workup,
including chest radiograph, isotope bone scan,
and abdominal ultrasonography scan, showed
no evidence of distant metastasis and the disease
was staged as T 2 N 2 M 0 , clinical stage III
according to 2002 Union Internationale Contre
le Cancer classification. The patient then underwent
treatment with conventional radiation
therapy using 2-dimensional techniques accompanied
with a total dose of 70 Gy at 2-Gy daily
fractions. The eustachian tubes were included in
the radiation field and part of the temporal
bones were out of the field, as shown in Figure 2.
Images obtained at the end of radiotherapy
showed slightly enhanced mucosa in the nasopharynx;
however, endoscopy revealed no residual
tumor. The patient was then followed up
regularly at the outpatient department without
residual tumor evidence. About 1 year after
initial treatment, the patient presented to the
same hospital with localized redness, swelling,
and pain occurring in the mastoid area. An
MRI showed an obvious mass in the left mastoid
(Figure 3). A biopsy from the external ear
was performed and used to diagnose recurrence.
Subsequently, the region of recurrence
was treated by intensity-modulated radiation
therapy (IMRT) with a dose of 69.96 Gy in 33
fractions. The tumor shrank slightly at the end
NPC Mastoid Recurrence after RT HEAD & NECK—DOI 10.1002/hed October 2011 1535

FIGURE 1. MR image before treatment of patient 1 showed a
well-circumscribed mass in the left lateral wall extending into
the ipsilateral parapharyngeal space.
FIGURE 2. The portal image of the radiation field of patient 1.
The eustachian tubes were included in the field and part of the
temporal bones were beyond the field.
FIGURE 3. MR image showed mastoid recurrence in patient 1
with an enhanced mass apparent in the left mastoid.
of radiotherapy; however, multiple bone metastases
occurred. After 4 cycles of chemotherapy
consisting of vinorelbine (40 mg, days 1 and 8)
and cisplatin (50 mg, days 2, 3, and 4), the disease
remained progression-free at the last follow-up
3 years after diagnosis.
Case 2. A 43-year-old woman with a 7-month
history of epistaxis and ear obstruction was
diagnosed with undifferentiated NPC by nasopharyngeal
mass biopsy. The enhanced mass
involved the right lateral wall extending to the
parapharyngeal space, clivus, petrous apex, and
right cervical nodes which were revealed on an
MRI scan (Figure 4). After a detailed clinical
workup, including chest radiograph, isotope
bone scan, and abdominal ultrasonography scan,
the disease was staged as T 3 N 1 M 0 , clinical stage
III according to 2002 Union Internationale
Contre le Cancer classification. Radiation therapy
was performed by IMRT using 9 coplanar
beams (6-MV photon) 40 apart with a dose of
7200 cGy divided into 33 fractions and delivered
in 7 weeks. Figure 5 illustrates the tumor targets,
dose distribution plan, and the portion of
the temporal bones covered by 5000 cGy isodose
curve. An enhanced T1-weighted MRI scan of
the nasopharynx obtained at the end of the
treatment revealed a high signal area, 1.5 cm
1.5 cm, which was suspected to represent a
region of persistent disease; however, endoscopic
biopsy from the persistent area was unable to
detect any residual tumor. The high-intensity
1536 NPC Mastoid Recurrence after RT HEAD & NECK—DOI 10.1002/hed October 2011

FIGURE 4. MR image before treatment of patient 2 showed a
well-circumscribed mass in the right lateral wall extending into
the ipsilateral parapharyngeal space.
feature was most likely radiation edema or
infection of the nasopharyngeal mucosa. Therefore,
routine follow-up was administered and
the disease remained recurrence free. Sixteen
months later, the patient was admitted to the
same hospital with complaints of right hearing
loss and hemicrania. On physical examination,
the patient was noted to have some signs of
inflammation including localized redness, swelling,
and increased skin temperature in the
mastoid area which measured approximately
3cm 2 cm. The patient received antiinflammatory
treatment for half a month, which had
no effect on suppressing the inflammation. An
MRI scan revealed a relatively defined mass
involving the right petrous bone and mastoid; a
biopsy from the external ear proved recurrence
(Figure 6). At the same time, the B-ultrasonic
examination showed multiple metastases in the
liver and retroperitoneal lymph nodes. The
patient was placed on palliative treatment with
traditional Chinese medicine and died 3 months
later.
DISCUSSION
The treatment failures for nasopharyngeal carcinoma
by radiotherapy are often attributed to
local persistence or recurrence, regional lymph
node metastasis, and distant metastasis. 1 The
FIGURE 5. CT slice at the level of the mastoid recurrence. The
gross target volume (GTV) is highlighted in red, and the planning
target volume (PTV) in sky blue. Part of the mastoid is covered
by 5000 cGy isodose curve. [Color figure can be viewed in
the online issue, which is available at wileyonlinelibrary. com.]
FIGURE 6. MR image showed mastoid recurrence in patient 2
with a defined mass involving the right mastoid.
NPC Mastoid Recurrence after RT HEAD & NECK—DOI 10.1002/hed October 2011 1537

local recurrence is usually identified in the
nasopharynx cavity or adjacent organs such as
sphenoid sinus, cavernous sinus, ethmoid sinus,
and clivus; however, mastoid recurrence is
extremely rare. To date, no related report citing
such a find could be located in the clinical literature.
It is speculated that eustachian tube
involvement may play an important role during
the process of mastoid recurrence. Anatomically,
the eustachian tube links the lateral wall of the
nasopharynx to the middle ear, which further
connects mastoid cells through the mastoid
antrum. Consequently, cancer cells may be able
to spread to the tympanum along the mucosal
lining then into the mastoid antrum. The 2
patients we report here each presented with
nasopharyngeal mass involving ipsilateral eustachian
tube, therefore, it is logical to extrapolate
that both of the mastoid recurrences
occurred ipsilaterally as described by the abovementioned
anatomical hypothesis. The reason
remains unknown why eustachian tube involvement
with NPC is common, yet mastoid recurrence
is relatively rare.
Both of our patients initially showed clinical
features similar to mastoiditis when first diagnosed
with mastoid recurrence, which suggests
that the differential diagnosis for mastoid swelling
after radiotherapy to treat the NPC should
include both mastoiditis and tumor recurrence.
Radiation-induced temporal bone tumors should
also be considered depending on the timing from
radiation therapy. In our 2 cases, the possibility
of a radiation-induced temporal bone tumor having
arisen from overlapping radiation fields was
disproved according to Cahan’s criteria 3–5 ; the
short interval period of recurrence (12 and
16 months, respectively) and the same histology
between the mass in the mastoid and the primary
tumor indicated it was a recurrent tumor.
To determine if inflammation was caused by
infection related to posttherapy eustachian tube
dysfunction, we administered antiinflammatory
treatment and observed no therapeutic benefit.
In addition, biopsy was critical to make the diagnosis
clear. It is worth noting that both of our
patients presented with distant metastasis
almost at the same time of mastoid recurrence,
therefore, it remains imperative that clinicians
be vigilant when patients previously irradiated
for nasopharyngeal malignancies present with
mastoid complaints. It remains unclear whether
patients with mastoid recurrence have an especially
high risk of distant metastasis or poorer
prognosis. Further studies are needed because
of the rarity of such cases.
CONCLUSIONS
This is the first report on mastoid recurrence after
radiotherapy for nasopharyngeal carcinoma
and the relationship between mastoid recurrence
and distant metastasis. We also suggest
that a definitive diagnosis of mastoiditis cannot
be made unless imaging and biopsy rule out the
possibility of a malignancy. Although the pathogenic
mechanisms underlying NPC recurrence
in mastoid tissues remains unknown, the clinical
reporting of these cases will encourage clinicians
to consider this rare recurrence and pay
attention to the relationship between mastoid
recurrence and distant metastasis.
REFERENCES
1. Lee AWM, Perez CA, Law SCK, Chua DTT, Wei WI,
Chong V. Nasopharynx. In: Perez CA, Brady LW, Halperin
EC, editors. Principles and Practice of Radiation Oncology.
Philadelphia: Lippincott Williams & Wilkins; 2008.
p 1583–1586.
2. Yi JL, Gao L, Huang XD, Li SY, Luo JW, Cai WM. Nasopharyngeal
carcinoma treated by radical radiotherapy
alone: ten-year experience of a single institution. Int J
Radiat Oncol Biol Phys 2006;65:161–168.
3. Cahan WG, Woodard HQ, Higinbotham NL. Sarcoma arising
in irradiated bone; report of 11 cases. Cancer 1948;
1:3–29.
4. Lustig LR, Jackler RK, Lanser MJ. Radiation-induced
tumors of the temporal bone. Am J Otol 1997;18:230–
235.
5. Goh YH, Chong VF, Low WK. Temporal bone tumours in
patients irradiated for nasopharyngeal neoplasm. J Laryngol
Otol 1999;113:222–228.
1538 NPC Mastoid Recurrence after RT HEAD & NECK—DOI 10.1002/hed October 2011