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Histologically benign pleomorphic adenoma of parotid with subcutaneous metastases
Otolaryngology–Head and Neck Surgery (2005) 133, 985-986
CASE REPORT
Histologically benign pleomorphic adenoma of parotid with subcutaneous metastases J. C. Muthusami, MD, M. R. Jesudason, MD S. R. B. Jesudason, MD, J. Subashini, MD, and Banumathi Ramakrishna, MD, Vellore, India
P
leomorphic adenoma is a benign salivary gland with potential for malignant transformation. When the malignant transformation occurs, the tumor develops a tendency for local recurrence and distant metastases and the histology of the tumor reflects all the cellular features of malignancy. However, there is an entity of pleomorphic adenoma which, while retaining benign histological features, tends to develop both local and distant recurrences despite adequate clearance at primary surgery. The reason for this remains unexplained and there is no predictor for this behavior. The rarity of its occurrence and inadequacy of information about its treatment prompted us to report our experience with one such case.
subcutis of skin of the skull (Fig 1A). The tumor was composed of ductular structures and a chondromyxoid stroma as illustrated in the nodule from the right parotid region (Fig 1B). The tumor was cellular in areas, but there was no cytological atypia, mitoses, necrosis, or vascular or perineural invasion. A diagnosis of metastasizing pleomorphic adenoma was made. In view of the locally recurrent nature of this tumor, external radiation of 50 Gray in 25 fractions, at 5 fractions per week, was given to the parotid bed by two oblique fields using a Cobalt-60 beam and to the tumor bed in the scalp using 7-MeV electrons. The patient is well and free from recurrence two years after the treatment.
CASE REPORT
DISCUSSION
A 31-year-old man presented with three subcutaneous nodules palpable on the frontal region of the scalp behind the hairline, each measuring 0.5 cm ⫻ 0.5 cm, and three subcutaneous nodules anterior to a surgical scar in the preauricular region overlying the masseter muscle; the largest of the nodules measured 1 cm ⫻ 1 cm. He had undergone right parotidectomy for pleomorphic adenoma elsewhere eight years ago and local excision of a recurrent swelling at the same site two years ago. The histology of the recurrent swelling, too, revealed pleomorphic adenoma. The second operation had resulted in facial nerve palsy. Fine needle aspiration cytology of the lesions in the preauricular region and excision biopsy of one of the scalp nodules revealed features consistent with benign pleomorphic adenoma. All the nodules were excised with wide margins of adjacent healthy tissue. Histology showed a nodule of tumor in the
Pleomorphic adenoma is the most common benign salivary gland neoplasm, occurring most often in the parotid gland. Malignant transformation in pre-existing benign pleomorphic adenoma and de novo malignant mixed tumors (carcinosarcoma) are known entities. There are reports of locally aggressive pleomorphic adenomas with regional lymph nodal and distant metastases in spite of maintaining a benign histology. Metastases have been discovered in long bones, skull, paranasal sinuses, kidney, liver, lung, central nervous system, retroperitoneum, and subcutaneous tissue.1,2 In view of this it is suggested that these tumors could be considered a third form of malignant pleomorphic adenoma.3 The histological features of malignancy –mitotic rate, cellular pleomorphism, local infiltration, vascular or lymphatic invasion–are characteristically absent in these tumors.1,2 No histological predictor has been identi-
From the Department of General Surgery—Unit I (Drs Muthusami, M.R. Jesudason, and S.R.B. Jesudason), Department of Radiation Oncology— Unit II (Dr Subashini), and Department of General Pathology (Dr Ramakrishna), Christian Medical College.
Reprint requests: J.C. Muthusami, Department of General Surgery—Unit I, Christian Medical College, Vellore, 632004, India; E-mail address: [email protected].
0194-5998/$30.00 © 2005 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved. doi:10.1016/j.otohns.2005.03.052
986
Otolaryngology–Head and Neck Surgery, Vol 133, No 6, December 2005 fied so far. Tumor ploidy and the presence of intravascular tumor in pleomorphic adenomas have not correlated with future development of metastases.1,4 It is suggested that myoepithelial cell proliferation within the tumor may predict an aggressive nature of lesion.5 Nevertheless, local recurrence of the disease prior to appearance of metastatic lesions has been a consistent observation in the clinical behavior of these tumors.1,2 The tumor reported here could be considered as locally aggressive type, the recurrence having occurred due to either incomplete excision or tumor spillage during the earlier surgery. The details from the report of his earlier surgery, however, suggest that a radical surgery for tumor eradication had been carried out then. The satellite recurrence in proximity to the parotid region eight years after the initial surgery could point towards malignancy. However, the total lack of histological evidence of malignancy weighs in favor of a benign lesion. This phenomenon suggests that the tumor cells tend to remain dormant within the locoregional capillary network, presenting later as clinically obvious disease. As this presentation is a rather rare occurrence, definite treatment protocols have not yet been outlined. The consensus, however, is that the primary treatment of the metastatic lesions should also be surgical excision. The role of adjuvant radiation has not been clearly stated, even though it has been given in select cases.2 The value of chemotherapy is doubtful.
REFERENCES
Figure 1 (A) Low-power view of scalp nodule showing tumor nodule in subcutis (H&E ⫻100). (B) Tumor in region of parotid showing ductular structures surrounded by chondromyxoid stroma (H&E ⫻200).
1. Wenig BM, Hitchcock CL, Ellis GL, et al. Metastasizing mixed tumor of salivary glands. A clinicopathologic and flow cytometric analysis. Am J Surg Pathol 1992 Sep;16(9):845–58. 2. Klijanienko J, El-Naggar AK, Servois V, et al. Clinically aggressive metastasizing pleomorphic adenoma: report of two cases. Head Neck 1997 Oct;19(7):629 –33. 3. Ruckley RW. Disease of the salivary glands. The New Aird’s Companion in Surgical Studies. Kevin G Burnand & Anthony E Young, 2nd ed. Churchill Livingstone; 1999. p. 392. 4. Altini M, Coleman H, Kienle F. Intra-vascular tumour in pleomorphic adenomas—a report of four cases. Histopathology 1997 Jul;31(1):55–9. 5. Cresson DH, Goldsmith M, Askin FB, et al. Metastasizing pleomorphic adenoma with myoepithelial cell predominance. Pathol Res Pract 1990 Dec;186(6):795– 800.
CASE REPORT
Histologically benign pleomorphic adenoma of parotid with subcutaneous metastases J. C. Muthusami, MD, M. R. Jesudason, MD S. R. B. Jesudason, MD, J. Subashini, MD, and Banumathi Ramakrishna, MD, Vellore, India
P
leomorphic adenoma is a benign salivary gland with potential for malignant transformation. When the malignant transformation occurs, the tumor develops a tendency for local recurrence and distant metastases and the histology of the tumor reflects all the cellular features of malignancy. However, there is an entity of pleomorphic adenoma which, while retaining benign histological features, tends to develop both local and distant recurrences despite adequate clearance at primary surgery. The reason for this remains unexplained and there is no predictor for this behavior. The rarity of its occurrence and inadequacy of information about its treatment prompted us to report our experience with one such case.
subcutis of skin of the skull (Fig 1A). The tumor was composed of ductular structures and a chondromyxoid stroma as illustrated in the nodule from the right parotid region (Fig 1B). The tumor was cellular in areas, but there was no cytological atypia, mitoses, necrosis, or vascular or perineural invasion. A diagnosis of metastasizing pleomorphic adenoma was made. In view of the locally recurrent nature of this tumor, external radiation of 50 Gray in 25 fractions, at 5 fractions per week, was given to the parotid bed by two oblique fields using a Cobalt-60 beam and to the tumor bed in the scalp using 7-MeV electrons. The patient is well and free from recurrence two years after the treatment.
CASE REPORT
DISCUSSION
A 31-year-old man presented with three subcutaneous nodules palpable on the frontal region of the scalp behind the hairline, each measuring 0.5 cm ⫻ 0.5 cm, and three subcutaneous nodules anterior to a surgical scar in the preauricular region overlying the masseter muscle; the largest of the nodules measured 1 cm ⫻ 1 cm. He had undergone right parotidectomy for pleomorphic adenoma elsewhere eight years ago and local excision of a recurrent swelling at the same site two years ago. The histology of the recurrent swelling, too, revealed pleomorphic adenoma. The second operation had resulted in facial nerve palsy. Fine needle aspiration cytology of the lesions in the preauricular region and excision biopsy of one of the scalp nodules revealed features consistent with benign pleomorphic adenoma. All the nodules were excised with wide margins of adjacent healthy tissue. Histology showed a nodule of tumor in the
Pleomorphic adenoma is the most common benign salivary gland neoplasm, occurring most often in the parotid gland. Malignant transformation in pre-existing benign pleomorphic adenoma and de novo malignant mixed tumors (carcinosarcoma) are known entities. There are reports of locally aggressive pleomorphic adenomas with regional lymph nodal and distant metastases in spite of maintaining a benign histology. Metastases have been discovered in long bones, skull, paranasal sinuses, kidney, liver, lung, central nervous system, retroperitoneum, and subcutaneous tissue.1,2 In view of this it is suggested that these tumors could be considered a third form of malignant pleomorphic adenoma.3 The histological features of malignancy –mitotic rate, cellular pleomorphism, local infiltration, vascular or lymphatic invasion–are characteristically absent in these tumors.1,2 No histological predictor has been identi-
From the Department of General Surgery—Unit I (Drs Muthusami, M.R. Jesudason, and S.R.B. Jesudason), Department of Radiation Oncology— Unit II (Dr Subashini), and Department of General Pathology (Dr Ramakrishna), Christian Medical College.
Reprint requests: J.C. Muthusami, Department of General Surgery—Unit I, Christian Medical College, Vellore, 632004, India; E-mail address: [email protected].
0194-5998/$30.00 © 2005 American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. All rights reserved. doi:10.1016/j.otohns.2005.03.052
986
Otolaryngology–Head and Neck Surgery, Vol 133, No 6, December 2005 fied so far. Tumor ploidy and the presence of intravascular tumor in pleomorphic adenomas have not correlated with future development of metastases.1,4 It is suggested that myoepithelial cell proliferation within the tumor may predict an aggressive nature of lesion.5 Nevertheless, local recurrence of the disease prior to appearance of metastatic lesions has been a consistent observation in the clinical behavior of these tumors.1,2 The tumor reported here could be considered as locally aggressive type, the recurrence having occurred due to either incomplete excision or tumor spillage during the earlier surgery. The details from the report of his earlier surgery, however, suggest that a radical surgery for tumor eradication had been carried out then. The satellite recurrence in proximity to the parotid region eight years after the initial surgery could point towards malignancy. However, the total lack of histological evidence of malignancy weighs in favor of a benign lesion. This phenomenon suggests that the tumor cells tend to remain dormant within the locoregional capillary network, presenting later as clinically obvious disease. As this presentation is a rather rare occurrence, definite treatment protocols have not yet been outlined. The consensus, however, is that the primary treatment of the metastatic lesions should also be surgical excision. The role of adjuvant radiation has not been clearly stated, even though it has been given in select cases.2 The value of chemotherapy is doubtful.
REFERENCES
Figure 1 (A) Low-power view of scalp nodule showing tumor nodule in subcutis (H&E ⫻100). (B) Tumor in region of parotid showing ductular structures surrounded by chondromyxoid stroma (H&E ⫻200).
1. Wenig BM, Hitchcock CL, Ellis GL, et al. Metastasizing mixed tumor of salivary glands. A clinicopathologic and flow cytometric analysis. Am J Surg Pathol 1992 Sep;16(9):845–58. 2. Klijanienko J, El-Naggar AK, Servois V, et al. Clinically aggressive metastasizing pleomorphic adenoma: report of two cases. Head Neck 1997 Oct;19(7):629 –33. 3. Ruckley RW. Disease of the salivary glands. The New Aird’s Companion in Surgical Studies. Kevin G Burnand & Anthony E Young, 2nd ed. Churchill Livingstone; 1999. p. 392. 4. Altini M, Coleman H, Kienle F. Intra-vascular tumour in pleomorphic adenomas—a report of four cases. Histopathology 1997 Jul;31(1):55–9. 5. Cresson DH, Goldsmith M, Askin FB, et al. Metastasizing pleomorphic adenoma with myoepithelial cell predominance. Pathol Res Pract 1990 Dec;186(6):795– 800.