Journal of Cancer Research and Therapeutics Medknow Publications on behalf of the Association of Radiation Oncologists of India (AROI) ISSN: 0973-1482 EISSN: 1998-4138 Vol. 6, Num. 3, 2010, pp. 330-332

Journal of Cancer Research and Therapeutics, Vol. 6, No. 3, July-September, 2010, pp. 330-332

Case Report

Papillary cystadenocarcinoma of submandibular salivary gland: A rare case report

Kavita Mardi, Sudarshan Sharma, Neelam Gupta

Department of Pathology, Indira Gandhi Medical College, Shimla, India

Correspondence Address:Kavita Mardi, 12-A, Type V Quarters, GAD Colony, Kasumpti, Shimla, Himachal Pradesh, India, kavitamardi@yahoo.co.in

Code Number: cr10077

PMID: 21119267

DOI: 10.4103/0973-1482.73346

Abstract

Keywords: Fine needle aspiration cytology, papillary cystadenocarcinoma, submandibular gland

Introduction

Papillary cystadenocarcinoma of the salivary gland is a rare malignant neoplasm. Major locations of this neoplasm are the parotid gland, the sublingual gland, and minor salivary glands, while occurrence in the submandibular gland is extremely rare. ^[1] We present cytological and histopathological findings of one such rare case arising in the submandibular salivary gland of a 67-year-old male.

Case Report

A 67-year-old male presented with a slow growing, painless swelling in the left submandibular region which he noticed since one year. On examination, there was a firm to hard swelling measuring 5 × 4 cm in size in the left submandibular region which was fixed to the underlying structures. Three lymph nodes belonging to the submandibular group were also enlarged. A computed tomography revealed a mass lesion in the left submandibular gland. Fine needle aspiration cytology (FNAC) of the swelling was done. Smear preparations were cellular with numerous papillary fragments, sheets of cells and single cells in a mucoid background [Figure - 1]. The tumor cells showed round bland appearing, eccentrically placed nuclei with inconspicuous nucleoli and abundant finely vacuolated basophilic cytoplasm [Figure - 2]. Signet ring cells were also seen in some of the clusters. Mitotic figures were not seen. Cyst macrophages were also seen in the background. Periodic acid schiff (PAS) stain revealed abundant PAS positive material in the cytoplasm of tumor cells. Cytological diagnosis of low grade papillary adenocarcinoma was suggested. The patient underwent left total submandibular gland extirpation under general anesthesia.

On gross examination there was a well encapsulated globular soft tissue mass measuring 5 × 4 × 3 cm. Cut section was partly solid and partly cystic. Three lymph nodes ranging in diameter from 0.25 cm to 0.5 cm were also dissected out from the specimen. Histologically, the neoplasm contained variably sized multicystic spaces lined by papillary structures [Figure - 3]. Foci of definite capsular invasion by tumor cells were present. The tumor cells revealed features similar to those seen on cytological smears. All the lymph nodes showed metastatic tumor deposits that completely replaced the lymph node parenchyma with only a rim of compressed lymphoid tissue at the periphery. Thus, the final diagnosis of low grade papillary cystadenocarcinoma was given.

Discussion

Papillary cystadenocarcinoma is an extremely rare malignant neoplasm that was first defined in 1991 by WHO. ^[2] It has also been called malignant papillary cystadenoma, low-grade papillary adenocarcinoma, or mucus-producing adenopapillary carcinoma. ^[3] It is defined by WHO as a low-grade malignant tumor characterized by cysts and papillary endophytic projections. The epithelium is cuboidal or low columnar. Mucus secreting cells can also be present. Malignancy is confirmed by nuclear pleomorphism, mitosis and infiltrative growth pattern. ^[4]

Cystadenocarcinomas account for about 2% of malignant salivary gland tumors. They are located in almost 50% of cases in the minor salivary glands, 45% in the parotid gland and only 5% in the submandibular gland. ^[5] Only a few cases of submandibular gland papillary cystadenocarcinoma have been reported in the literature. ^[1] Most of the patients presented as a slowly growing and asymptomatic mass. Despite its low-grade nature, there have been several reports indicating that papillary cystadenocarcinoma may have a more aggressive behavior, and higher grade pathological features. ^[4]

Papillary cystadenocarcinomas of the salivary glands can be accurately diagnosed on FNAC. Kapila et al. ^[6] have described the cytological features in a series of four cases of papillary cystadenocarcinomas of the parotid glands. Smear preparations in all four cases were cellular, with numerous papillary projections, single cells, and sheets of cells in varying proportion in a proteinaceous to mucoid background. The background mucin was present in varying proportions. The cells were cuboidal to tall columnar with basal nuclei and mild pleomorphism. The cytoplasm was dense in three cases with variable amounts of mucin. In one case, the epithelial cells resembled mucin-secreting goblet cells, while in another case the cytoplasm showed multiple vacuolations. Mitotic figures were rare. Lymphoid tissue was seen in one case while macrophages and giant cells were seen in two cases.

Aloudah et al. ^[7] have recently described the cytological features of low grade papillary cystadenocarcinoma in the parotid gland. The cytological features in their case consisted of bland appearing papillary and micropapillary neoplasm with variable cellularity and absence of cytological atypia. The cells were small to medium in size with abundant and occasionally vacuolated cytoplasm. The nuclei were eccentric, bland appearing, round, and at the most part uniform in size without anaplasia or mitotic activity. The background was mucoid. We also found similar cytological features in our case.

These tumors need to be differentiated from mucoepidermoid carcinoma and papillary cystic variant of acinic cell carcinoma (ACC-PCV) on FNAC. Mucoepidermoid carcinomas show a dirty mucinous and necrotic background. In addition, most of these case show malignant squamous and/or hybrid cells. In ACC-PCV, cells are mildly pleomorphic and intracellular mucin vacuoles are not found. Tumor cells with a small vacuolated, soap-bubble appearance of the cytoplasm are common findings of both cystadenocarcinoma and ACC-PCV. However, special stains for mucin are negative in acinic cell carcinoma cells. Both polymorphous low-grade adenocarcinoma (PLGAC) and papillary cystadenocarcinoma (PCAC) are low-grade papillary salivary carcinomas. But PLGAC showed stromal fragments and hyaline globules resembling pleomorphic adenoma or adenoid cystic carcinoma. Some authors have described FNAC efficacy of 80% in relation to salivary gland cystadenocarcinomas. ^[8] In the literature, the lesion most often confused with cystadenocarcinomas are Warthin′s tumor or salivary gland cysts. ^[9] However, Warthin tumors show monolayered sheets of oncocytes and many lymphocytes in a background of amorphous, granular debris. Salivary gland cysts are less cellular and show some mildly atypical epithelial cells and macrophages in a mucoid background.

The management suggested for low grade cystadenocarcinomas is similar to that advocated for other low grade salivary gland adenocarcinomas. ^[10] Complete surgical excision is considered as adequate in these cases. A number of high grade cystadenocarcinomas have been documented in the literature. ^[1] Histological grading of these tumors is important as the high grade tumors require complementary radiotherapy. Beppu et al. ^[11] reviewed 27 patients with submandibular gland carcinoma and concluded that supraomyohoid neck dissection is suitable for N0 cases of submandibular gland cancer because of four reasons: 1) rate of occult neck lymph node metastasis in submandibular gland cancer is high, 2) pathological neck lymph node metastasis in N0 cases and latent neck lymph node metastasis were observed in level 2 and level 3, 3) the prognosis of cases with neck lymph node metastasis was poor, and 4) same skin incision can be used not only for the primary resection but also for the neck dissection.

To conclude, papillary cystadenocarcinoma of the submandibular salivary gland is an extremely rare entity that can be reliably diagnosed on FNAC. Recognition of subtle cytologic features may be useful in the differential diagnosis. Correlations with the clinical and radiological features are also of great importance in arriving at correct diagnosis.

References

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