Year : 2015 | Volume
: 11 | Issue : 3 | Page : 655-
Mucoepidermoid carcinoma of parotid gland as a subsequent neoplasm in children treated for acute lymphoblastic leukemia
Reghu K Sukumaran Nair, Binitha Rajeswari, Priyakumari Thankamony, Kusumakumary Parukuttyamma
Division of Pediatric Oncology, Regional Cancer Center, Thiruvananthapuram, Kerala, India
Dr. Binitha Rajeswari
Division of Pediatric Oncology, Regional Cancer Center, Thiruvananthapuram, Kerala State - 695 011
We report two cases of mucoepidermoid carcinoma occurring as a second neoplasm following treatment for acute lymphoblastic leukemia. Both patients underwent parotidectomy as the primary treatment. One of them received irradiation in addition to surgery. We discuss the risk of developing MEC as a second malignancy, prognosis, and treatment options.
|How to cite this article:|
Sukumaran Nair RK, Rajeswari B, Thankamony P, Parukuttyamma K. Mucoepidermoid carcinoma of parotid gland as a subsequent neoplasm in children treated for acute lymphoblastic leukemia.J Can Res Ther 2015;11:655-655
|How to cite this URL:|
Sukumaran Nair RK, Rajeswari B, Thankamony P, Parukuttyamma K. Mucoepidermoid carcinoma of parotid gland as a subsequent neoplasm in children treated for acute lymphoblastic leukemia. J Can Res Ther [serial online] 2015 [cited 2020 Sep 30 ];11:655-655
Available from: http://www.cancerjournal.net/text.asp?2015/11/3/655/136032
Acute lymphoblastic leukemia (ALL) chemotherapy is associated with subsequent neoplasms (SN).  Long term follow-up studies in children receiving chemotherapy conducted by the COG and BFM groups have established that cumulative incidence of any second neoplasm varied between 1.18% at 5 years to 3.3% at 15 years, respectively. , Most common subsequent malignancies following ALL therapy include acute myeloid leukemia (AML), CNS tumors, and thyroid tumors.  We report two cases of mucoepidermoid carcinoma (MEC) in two children who received chemotherapy for ALL.
A four-year-old boy was diagnosed as pre-B-cell acute lymphoblastic leukemia, standard risk and received chemotherapy as per the BFM 95 ALL protocol. On completion of treatment, disease was in remission, as documented by bone marrow study and clinical examination. Two years after completion of treatment, he presented with a swelling below right ear lobe. The swelling was painless, approximately 1 cm in size, mobile, and hard in consistency. FNAC was done, and pathological examination revealed scattered lymphocytes and histiocytes. CT scan of the parotid region showed a well-defined hyperdense lesion in the superficial lobe of the right parotid gland without extension into adjacent tissue. Patient underwent conservative parotidectomy. Histopathology of the tumor was reported as intermediate grade mucoepidermoid carcinoma. He underwent radiation therapy with 180 cGy in 28 fractions. He remained under follow-up. Two years later, the swelling re-appeared at the same site. FNAC was reported as recurrence of MEC. Surgical excision was done again. At one year of follow-up since the second surgery, he has no recurrence.
A three-year-old girl was diagnosed as pre-B-cell acute lymphoblastic leukemia, standard risk and was treated with chemotherapy as per the BFM 95 ALL protocol. Disease was in remission at the end of treatment as documented by bone marrow study and clinical examination. She did not receive any prophylactic cranial radiotherapy. Eight months after completion of treatment, she presented with a swelling behind the left ear. An excision biopsy of the lesion was done. Histopathology was reported as low grade mucoepidermoid carcinoma of the parotid gland. Surgical review was done, and she underwent a superficial parotidectomy. Residual tumor was present on re-exploration, but excision was incomplete due to extensive adhesions and scarring from previous surgery. Histopathology was reported as intermediate grade MEC of parotid gland with positive margins. Post-operative CT scan of the parotid region was normal. In view of high risk for facial nerve injury, further local treatment was deferred. She was kept on follow-up, and regular imaging is being done to detect any recurrence.
Children receiving chemotherapy are at risk of developing subsequent neoplasms, and the risk does not appear to plateau even after 15 yrs of follow up.  The types of SNs also vary in their type and risk. Parotid tumors are rare second neoplasms occurring in such a setting. But, the estimated standardized incidence rate ratio (SIR) for parotid tumors as SN following chemotherapy is estimated to be high, second only to acute myeloid leukemia. ,, Among reported cases of salivary gland tumors following chemotherapy, MEC is the most common. ,
The significance of these two cases pertains to the facts that both of them did not receive irradiation during treatment for ALL and had very early presentation following treatment (one at eight months and the other at two years following treatment). In a recent review of MEC as second neoplasms in children receiving chemotherapy, it was seen that a significant number of cases occurred in children who had received chemotherapy alone. The latent period for the occurrence of parotid tumor following ALL treatment ranges from 1 to 27 years with a median latency of eight years.  Though the most significant risk factor for developing SNs is radiotherapy (RT), latent period is shortest for children receiving chemotherapy alone, than in those treated with RT alone or RT and chemotherapy.  The early occurrence of MEC in these two cases underscores this fact. Chemotherapy itself may be contributory to development of parotid tumors, and radiation therapy may not be the only major risk factor.  Both the children received Vincristine, Daunorubicin, L-asparaginase, Cyclophosphamide, Cytosine arabinoside, Methotrexate, 6 Mercaptopurine, and steroids during the treatment for ALL. Anthracyclines and epipodophyllotoxins have been associated with increased risk of SN, mainly second hematological malignancies.  However, there are no studies establishing a link between mucoepidermoid carcinoma of salivary glands and any particular chemotherapeutic agent.
Mucoepidermoid carcinomas are graded as low grade, intermediate grade, and high grade. Though the histopathology in these two cases was intermediate grade, MEC following chemotherapy is usually of a low grade, conferring a favorable prognosis in these cases.  The MEC occurring as a second neoplasm is generally detected earlier, and the chance of node negative disease is higher, because these children are under close follow-up and surveillance. Therefore, MEC occurring as a second neoplasm appears to have a good prognosis with overall survival of more than 90%. Surgery is the mainstay in the management of MEC of parotid gland.  Parotidectomy (superficial or total), without damaging the facial nerve, is the best approach. Tumor resection or limited excision of the parotid and sub-mandibular glands carry a high risk of incomplete tumor removal.  Simultaneous neck dissection is recommended only when neck metastases are clinically detected.  The role of radiation is controversial, especially in children. Adjuvant irradiation is given for high grade lesions, node-positive disease, incomplete surgery, and large aggressive tumors. ,, Current evidence does not recommend chemotherapy for MEC.
The occurrence of MEC in children treated for ALL without irradiation emphasizes the need for routine screening programs for subsequent neoplasms by conducting regular physical, laboratory, and radiological examination.
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