Primary Malignant Lymphoma of the Salivary Glands

Fine-needle aspiration biopsy of large-cell undifferentiated carcinoma of the salivary glands: presentation of two cases, literature review, and differential cytodiagnosis of high-grade salivary gland malignancies

Primary undifferentiated carcinoma of the salivary glands is a rare, high-grade neoplasm which accounts for a very small number (1-5.5%) of malignant salivary gland tumors. The large-cell variant (LCU) is less well-characterized than the small-cell form. We report on the fine-needle aspiration (FNA) biopsy findings of 2 cases of LCU, one arising in the parotid gland, and the other in a buccal mucosa accessory salivary gland. The 2 cases were similar in composition: isolated and loosely cohesive large cells with abundant cytoplasm, and variability pleomorphic nuclei with prominent nucleoli. One case also featured multinucleated tumor giant cells and macrophage polykaryons; the latter has not previously been described in FNA biopsies of LCU. There was no evidence of squamous, myoepithelial, or widespread mucinous differentiation by morphological, cytochemical, or immunohistochemical analyses (focal rare mucin production identified on special stains in one case). The differential diagnosis is lengthy and consists of other high-grade primary salivary gland malignancies as well as metastatic lesions, including melanoma. The pattern of immunohistochemical reactivity (positive keratin, negative S-100, and HMB-45 antigens), and lack of conspicuous mucin production of significant lymphoidinfiltrate, were useful in establishing the correct diagnosis.

Diagnosis and treatment of malignant lymphoma of the parotid gland

BACKGROUND

To correlate the imaging and pathological features and to discuss therapeutic modalities and the prognosis of malignant lymphoma originating in the parotid gland, which is relatively rare.

METHODS

The subjects were five patients with malignant lymphoma originating in the parotid gland. Three and two patients were stage I and stage II, respectively. CT examination was applied to all, whereas only one case was examined by MRI. All were treated with radiotherapy following surgery or chemotherapy. Three patients underwent combination chemotherapy, such as with MACOP-P or VEPA, following surgery.

RESULTS

Although malignant lymphoma originating in the parotid gland is histologically described as low-grade non-Hodgkin's lymphoma, two and one of the cases were classified as intermediate and high grade in the present series, respectively. These three exhibited a tendency for infiltration into the adjacent tissue and tumor inhomogeneity in the imaging findings, suggesting a correlation with histologically intermediate or high-grade non-Hodgkin's lymphoma. It was successfully controlled by radiotherapy, with dosages ranging from 40 to 44 Gy. The patients were followed for 2-8 years. No relapse was found in the three patients with stage I. However, both stage II patients had relapses and were subjected to additional radiotherapy combined with chemotherapy. Since then, no tumor relapse has been noted at either this or other sites.

CONCLUSIONS

Malignant lymphoma including intermediate or high grade originating in the parotid gland indicated satisfactory prognosis following radiotherapy and chemotherapy.

Primary parotid lymphoma: the effect of International Prognostic Index on outcome

Since the reported survival and failure-free survival (FFS) of adults with primary parotid non-Hodgkin's lymphoma (NHL) is variable, we reviewed our experience of untreated adults with primary parotid NHL. Patients were eligible if they presented to the University of Texas M. D. Anderson Cancer Center Cancer between 1980 and 1995 with parotid enlargement and if the diagnosis of lymphoma was verified according the Working Formulation. Medical records were reviewed to determine Ann Arbor Stage (AAS), the International Prognostic Index (IPI) score, response to therapy, relapse, FFS, and survival. We identified 39 untreated adults with primary parotid NHL representing 1% of all lymphomas and 8.6% of all untreated parotid neoplasms. Three patients were excluded because of suboptimal therapy, leaving 36 patients eligible for outcome analysis. Of the 18 patients with low-grade NHL, two were treated with radiotherapy, eight with chemotherapy and radiotherapy, seven with chemotherapy only, and one with antibiotics. The complete remission (CR) rate was 94%, and with a median follow-up of 36 months for surviving patients the survival and failure-free survival (FFS) at 5 years were 94% and 78%, respectively. The 5-year FFS were not statistically different between patients with early (I or II) or advanced (III or IV) AAS (83% and 74%, respectively; p > 0.05) and favorable (0 or 1) or unfavorable (> 1) IPI scores (73% and 100%, respectively; p > 0.05). All 18 patients with intermediate-grade NHL were treated with doxorubicin-based chemotherapy which was followed by radiotherapy in six. The CR rate was 89%, and with a median follow-up of 51 months for surviving patients the survival and FFS at 10 years were 80% and 72%, respectively. In this group 10-year FFS was better in early than in advanced AAS (100% vs 0%, respectively; p = 0.01) and in favorable (0 or 1) than in unfavorable (> 1) IPI scores (86% vs 20%, respectively; p < 0.01). We conclude the the FFS of patients with low-grade NHL is 78% and not affected by AAS or IPI score. The FFS of patients with intermediate-grade NHL appears comparable with that of NHLs of other primary sites, being 86% for those with IPI < or = 1 and 20% for those with IPI 1. Patients with IPI > 1 should be entered on investigational protocols aiming to increase FFS.