4 Discussion
We have reported the surgical and biochemical outcomes for head and neck
TIO. PMT resection in the head and neck region was associated with high
local recurrence/residual disease rate (56%), which was significantly
higher than that of the extremities and trunk (25%). However,
biochemical remission was achieved in the majority of the patients after
re‑excision at the last follow-up (89%, 8 out of 9).
Most of the previous reports concerning the head and neck TIO were small
case series often mixed with other sites, which had short-term
follow-ups within two years after surgical
excision.5-7,16,17 Pal et al. reported surgical
excision in 30 cases TIO in various sites, which resulted in remission
in 73% of the patients, whereas disease persistence and tumor
recurrence in 18% and 9% of the cases,
respectively.18 Zhu et al. analyzed 43 patients with
sinonasal tumors, including PMT, odontogenic fibroma, and
hemangiofibroma, which were associated with TIO.19 In
the series, a high local recurrence rate or nonremission was found
(12%). The other report illustrated the seven patients with TIO in the
paranasal sinus, intracranial, and maxilla who underwent surgical
excision.20 They demonstrated that four of seven
(57%) had persistent illness after surgical removal, and three patients
were managed by external beam radiation treatment for recurrent tumors.
Consistent with these reports, our data demonstrated a great residual
disease/local recurrence rate in the head and neck PMT. However, in most
of our patients, biochemical remission was attained after re-excision
without radiation treatment. We believe that re-excision of the
residual/local recurrent tumor without radiation therapy is a practical
treatment option. In contrast to our findings, Li et al. reported that
the refractory rate was the lowest in head and neck tumors (7.5%)
compared to other sites.8 However, they did not state
the details of localization of the tumor, surgical methods, and
complications after surgery for the head and neck tumors. In our
residual/recurrent cases, craniotomy was conducted due to the proximity
of the brain in three cases. The surgical process, surgical margin, and
localization of the tumor presumably contributed to the differences in
outcomes.
Complete surgical excision with wide margins was the cornerstone of PMT
management.21,22 The main surgical challenge of
resection of head and neck PMT is the difficulty of obtaining a clear
margin because of the anatomical complexity and proximity of the brain
or other important organs. Previous studies showed that soft tissue PMT
with an irregular boundary observed on imaging tended to infiltrate into
subcutaneous fat.21 Furthermore, bone PMT demonstrated
invasion into cancellous and cortical bone.22 These
findings suggest that in patients with these imaging features, resection
of infiltrative margin in soft tissue tumor or resection of thinned
cortical bone may be required to reduce the risk of local
recurrence/residual disease. However, excessive removal of the
surrounding tissues may increase the risk of surgical morbidity,
particularly in cases of head and neck PMT. Surgeons need to balance the
risk of surgical morbidity and local recurrence/residual disease.
TIO is a rare and underreported condition because treating clinicians
are unaware of its characteristic, clinical, and biochemical
profiles.3 Through this research, we highlighted our
experience with TIO cases including the head and neck regions. A
significant time gap between the initial presentation until the
diagnosis existed even in the presence of severe symptoms in our series.
Other challenges included the difficulty of distinguishing PMT from
other incidental findings on imaging studies. Especially in the head and
neck area, apical periodontitis was encountered, which was suspected to
be a tumor that caused TIO (Fig. 3a–f). Furthermore, X-linked
hypophosphatemic rickets/osteomalacia is one of the possible
differential diagnoses in patients with osteomalacia who have abnormal
findings in the alveolar bone area, which can lead to a variety of
dental complications, including apical
periodontitis.23 These findings will raise awareness
and provide valuable insights into the treatment of issues associated
with this rare disease in the head and neck region.
We would like to acknowledge the limitations of our study. First, this
study involving a heterogeneous and small group of patients. Second, our
study is a retrospective review and there are selection, indication, and
expertise biases concerning both the initial surgery and subsequent
procedures. Third, patients were treated over two decades, and we were
unable to adjust for important confounders, including evolution in
treatment strategies and medical/surgical/imaging management/techniques.
A histopathology and radiology review at an institutional
multidisciplinary board meeting, we believe, has reduced these biases.
In conclusion, PMT in the head and neck area demonstrated a high local
recurrence/residual disease rate. However, biochemical remission was
achieved in most patients at the last follow-up. Before definitive
resection, surgeons should discuss with their patients the difficulty of
obtaining clear margins due to the complex anatomy of the region and the
proximity of important organs.