G. MANNELLI ET AL.
Open Access IJOHNS
235
were compared. No differences existed. No evidence of
malignancy was identified. Two of these patients died as
a direct result of their metastases at 3 and 2 years, seven
patients were alive without disease, and two patients died
of unrelated causes. More probably, the metastatic capa-
bility reflects the accumulation of key genetic alterations,
a sequential process that causes histological and biologi-
cal progression [2]. El-Naggar et al. [8] considered that
the lack of recognized histologic parameters of malig-
nancy raises the possibility that a small subset of pleo-
morphic adenomas may have an area of submicroscopic
alterations that may subsequently pursue a malignant
course.
Some authors investigated the possible correlation
between expression of oncogenes and tumor suppressos
genes and metastasizing pleomorphic adenoma, in order
to find a genetic reason of its behavior [9]. Unfortunately,
no correlation has been found between specific chromo-
somal defects and tumor recurrence and/or metastases.
4. Conclusions
MPA is a low-grade malignant tumor [3], which shows
the 58% disease-specific 5-years survival and about 50%
of disease-free survival rate, with a mortality rate of
about 20% [1,10]. It should not be underestimated. Mul-
tiple metastases are fatal, and their developing and pres-
ence in multiple sites, within the first 10 years after the
initial diagnosis, are independent predictors of worse
survival [10].
Usually, local recurrence is detected first and metasta-
sis second, but in case of accidental metastasis in a pa-
tient with a history of pleomorphic adenoma or of its
local recurrences it would be better to investigate the
presence of a local recurrence, which is found in 80% of
cases. We recommend, in order to prevent possible local
recurrences and distant metastasis, performing superficial
parotidectomy with facial nerve preservation to obtain a
meticulous resection of the primary pleomorphic ade-
noma, which is usually curative. On the other hand, che-
motherapy and radiotherapy still present a limited value
[11] as well as hormonal treatment [12].
Due to the limited number of reported cases, it is dif-
ficult to understand the biology of MPA as distinct from
non-MPA and to identify a specific follow-up protocol,
but we agree that the metastatic disease should be treated
surgically.
5. Acknowledgements
This manuscript is approved by all authors and all of
them have participated in writing and correcting of this
work. Further, all authors assure that manuscript has not
been published nor is under approving by other journals
or editors and they have not any conflict of interest, fi-
ancial or otherwise. n
REFERENCES
[1] B. M. Wenig, C. L. Hitchcok, G. L. Ellis and D. R.
Gnepp, “Metastasizing Mixed Tumor of Salivary Gland:
A Clinicopathologic and Flow Cytometric Analysis,”
American Journal of Surgical Pathology, Vol. 16, No. 9,
1992, pp. 845-858.
http://dx.doi.org/10.1097/00000478-199209000-00003
[2] G. L. Ellis and P. L. Auclair, “Malignant Epithelial Tu-
mors,” In: G. L. Ellis and P. L. Auclair, Eds., Tumors of
the Salivary Glands, Armed Forces Institute of Pathology,
Washington DC, 1996, pp. 39-136.
[3] V. Manucha and O. B. Ioffe, “Metastasizing Pleomorphic
Adenoma of Salivary Gland,” Archives of Pathology &
Laboratory Medicine, Vol. 132, No. 9, 2008, pp. 1445-
1447.
[4] G. R. Youngs and P. J. Scheuer, “Histologically Benign
Mixed Parotid Tumor with Hepatic Metastasis,” Journal
of Pathology, Vol. 109, No. 2, 1973, pp. 171-173.
http://dx.doi.org/10.1002/path.1711090211
[5] V. Raja, C. China, K. H. Masaki and G. Nakano, “Benign
Metastasizing Pleomorphic Adenoma,” Journal of Clini-
cal Oncology, Vol. 20, No. 9, 2002, pp. 2400-2403.
[6] F. W. Foote Jr. and L. E. Frazell, “Tumors of the Major
Salivary Glands,” Cancer, Vol. 6, 1953, pp. 1065-1133.
http://dx.doi.org/10.1002/1097-0142(195311)6:6<1065::
AID-CNCR2820060602>3.0.CO;2-0
[7] S. A. R. Nouraei, M. S. Ferguson, P. M. Clarke, A. San-
dison, G. S. Sandhu, L. Michaels and P. Rhys-Evans, “Me-
tastasizing Pleomorphic Salivary Adenoma,” Archives of
Otolaryngology—Head and Neck Surgery, Vol. 132, No.
7, 2006, pp. 788-793.
http://dx.doi.org/10.1001/archotol.132.7.788
[8] A. El-Naggar, J. G. Batsakis and S. Kessler, “Benign Me-
tastatic Mixed Tumours or Unrecognised Salivary Gland
Carcinomas?” Journal of Laryngology & Otology, Vol.
102, No. 9, 1988, pp. 810-812.
http://dx.doi.org/10.1017/S0022215100106528
[9] Y. Jin, C. Jin, K. Arheden, et al., “Unbalanced Chromo-
somal Rearrangements in a Metastasizing Salivary Gland
Tumour with Benign Histology,” Cancer Genetics and
Cytogenetics, Vol. 102, No. 1, 1998, pp. 59-64.
http://dx.doi.org/10.1016/S0165-4608(97)00301-4
[10] J. Klijanienko, A. El-Naggar, V. Servois, J. Rodriguez, P.
Validire and P. Vielh, “Clinically Aggressive Metastasiz-
ing Pleomorphic Adenoma: Report of Two Cases,” Head
and Neck, Vol. 19, No. 7, 1997, pp. 629-633.
http://dx.doi.org/10.1002/(SICI)1097-0347(199710)19:7<
629::AID-HED11>3.0.CO;2-Y
[11] J. Paris, F. Facon, M. A. Chrestian, A. Giovanni and M.
Zanaret, “Recurrence of Pleomorphic Adenomas of the
Parotid: Changing Attitudes,” Revue de Laryngologie-
Otologie-Rhinologie, Vol. 124, No. 4, 2003, pp. 229-234.
[12] A. S. Glas, H. Hollema, R. E. Nap and J. T. Plukker, “Ex-
pression of Estrogen Receptor, Progesterone Receptor,
and Insulin-Like Growth Factor Receptor-1 and of MIB-1
in Patients with Recurrent Pleomorphic Adenoma of the
Parotid Gland,” Cancer, Vol. 94, No. 8, 2002, pp. 2211-
2216. http://dx.doi.org/10.1002/cncr.10445