Plasmablastic lymphoma (PBL) is a diffuse large B-cell lymphoma, a new entity, the incidence of which is increasing, predominantly in the oral cavity of immunocompromised patients, most of whom are infected with human immunodeficiency virus (HIV); only four cases have been reported in non-HIV-infected patients. This report details two cases of PBL of the oral cavity in immunocompetent patients. In both cases, the tumour manifested as a solitary, firm mandibular swelling with dense infiltration of plasma and blastoid cells in the stroma with strong positivity for CD 138 and negativity for CD 20. The patients received radiotherapy and chemotherapy, which resulted in complete remission of the lesion. This is the only case report of two cases of PBL in the oral cavity in immunocompetent patients in which both patients received treatment and showed complete remission of the lesion.
Non-Hodgkin’s lymphoma (NHL) comprises a group of malignant lympho-proliferative diseases and often disseminates into extra-nodal sites (33%). The commonest site of extra-nodal presentation of NHL is the gastrointestinal tract. Primary extra-nodal lymphomas of the head and neck region are relatively rare and comprise about 4% of all head and neck tumours, with Waldeyer’s ring being the most common site of presentation. The involvement of the oral cavity accounts for 0.1–5% of extra-nodal lymphomas with the palate being the predominant site .
Plasmablastic lymphoma (PBL) is an aggressive subtype of non-Hodgkin’s lymphoma, which frequently arises in the oral cavity of human immunodeficiency virus (HIV) infected patients . Approximately 60 cases of PBL have been reported to date of which only four cases were associated with non-HIV patients .
The usual presentation of the lesion in the oral cavity is that of a single solitary, soft to firm asymptomatic mass, which shows osteolytic activity around the edges of the lesion on a radiographic image. The peak incidence of age for oral PBL is 41 years; it is more common in males than in females with a predilection of 5:1.
This paper reports two rare cases of PBL occurring in the mandible as a primary intraoral manifestation in immunocompetent patients; both the patients received treatment.
Case report 1
A 65-year-old man presented with the chief complaint of pain and swelling in the anterior region of the mandible for 2 months ( Fig. 1 ). On examination, a firm, tender solitary swelling, 5 × 3 cm in size, extending from the lower left canine to the lower right premolar tooth was observed. The overlying mucosa was normal with no indurations or ulceration. The teeth associated with the lesion were Grade II mobile. A panoramic radiograph showed an ill-defined osteolytic lesion in the anterior mandible. A provisional diagnosis of giant cell lesion was made.
An incisional biopsy was performed and microscopic examination revealed hyperkeratinized stratified squamous epithelium with atrophic changes. The stroma was predominately mature and collagenous with dense infiltration of plasma and blastoid cells. A provisional histological diagnosis of round cell tumour was made. A final diagnosis of PBL was made on the basis of an immunohistochemical study that showed tumour cells strongly positive for CD 138 and negative for CD 20 ( Fig. 2 ). The results of routine blood investigations were under normal limits and the patient was seronegative for HIV. Based on Ann Arbor classification, the lesion was classified as Stage IE (lesion involving a single extra lymphatic organ or site).
Combined radiotherapy and chemotherapy was planned and the patient underwent radiotherapy of 45 Gy in 25 fractions (1.8 Gy/fraction) over a field of 5 × 10 anterior and 5.5 × 10 laterally for 5 weeks. Complete remission of the lesion was observed following 5 weeks of radiotherapy, after which the patient underwent chemotherapy on a standard CHOP regime. Day 1: cyclophosphomide 750 mg/m 2 , doxorubicin/adriamycin 50 mg/m 2 and vincristine 1.4 mg/m 2 . Day 1 to Day 5: prednisolone (oral) 100 mg (this cycle was repeated after 21 days with a review of complete blood count and liver function tests) for four courses. After 1 year of follow up the patient is in excellent health with no signs of recurrence.
Case report 2
A 70-year-old man presented with a chief complaint of pain and swelling in the left posterior region of the mandible, which had been associated with spontaneous bleeding from the lesion for 3 months ( Fig. 3 ). Examination revealed a proliferative growth involving the left mandibular alveolus, measuring 4 × 3 cm, extending from the left lower premolar to the third molar region. The teeth associated with the lesion were Grade I mobile and the left submandibular lymph node was palpable. Panoramic radiography did not reveal any significant bone loss around the lesion. A provisional diagnosis of pyogenic granuloma was made.
Histopathological study of the biopsied tissue revealed hyperplastic squamous epithelium and the underlying stroma showed large cells, which were lymphoid in nature. Multinucleated cells were also admixed with lymphocytes and plasma cells. A provisional diagnosis of round cell tumour was made. Immunohistochemical (IHC) staining was performed and tumour cells expressed strong positivity for CD 138 with lambda chain restriction and negativity for CD 20, CK and CD 30 ( Fig. 4 ). Based on these findings a final diagnosis of PBL was made. A routine investigation of the blood and immune status revealed the patient was seronegative for HIV on ELISA, which was confirmed on Western Blot.