Extramedullary plasmacytoma: Tumor occurrence and therapeutic concepts-A follow-up

Abstract

Background: Extramedullary plasmacytoma (EMP) is a solitary tumor consisting of neoplastic plasma cells, with very little to no bone marrow involvement. EMPs are usually located in the head and neck region, but can also occur along the digestive tract, in lungs, or extremities.

Methods: Following our publication on EMP, which appeared in 1999 (Cancer 85:2305-14), we conducted a literature search for EMP-related reports published between 1999 and 2021. The documented cases, as well as 14 of our own patients from the ENT Clinic Erlangen, were extensively analyzed.

Results: Between 1998 and 2021, 1134 patients with EMP were reported, for whom information about the tumor localization was available. Among those, 62.4% had EMP in the head and neck area and 37.6% in other body regions. Data on therapy were reported in 897 patients, including 34.3% who received radiation, 28.1% surgery, 22.6% a combination of surgery and radiation, and 15.9% another therapy. In 76.9% patients no recurrence or transformation to multiple myeloma (MM) was reported, 12.8% showed local recurrence and 10.2% developed MM. Radiotherapy alone was associated with a tendency for increased occurrence of MM. In patients with EMP of head and neck area, combination therapy (surgery and radiation) resulted in a 5-year overall survival rate of 98.3%, surgery alone of 92.4%, and radiotherapy of 92.7%.

Conclusions: Collectively, our analyses indicate that surgical resection alone can achieve long-term tumor control in patients with EMP, if the tumor can be removed within safe limits without causing serious functional impairment. However, if this is not certain, either radiation or a combination of surgery and radiation therapy is suggested as an effective means of local tumor control.

Keywords: extramedullary plasmacytoma; non-Hodgkin lymphoma; survival; therapy; tumor outcomes.

FIGURE 1

Representative images of an extramedullary plasmacytoma. The tumor cells show abundant basophilic cytoplasm, a small perinuclear “hof”, larger nuclei with remarkable nucleoli resembling immature plasma cells. Blastoid features are absent. Plasmacytoma cells express prototypical plasma cell markers (Vs38c, CD138) and show a light chain restriction (abundant expression of kappa light chains, completely negative for lambda light chains). Typically, CD20 is negative while the pan‐B‐cell/origin marker CD79a shows a specific positivity. Similar to plasma cell myelomas (multiple myeloma), the EMP cells show a strong aberrant CD56 and CD117 (c‐Kit) expression. All images were taken at 400x magnification from digitalized whole‐slide stainings, scale bar: 20 μm.

FIGURE 2

Most frequent treatment options (A, B) and overall progression (C, D) of extramedullary plasmacytoma (EMP) according to literature research. Other therapies in the UAD included chemotherapy (1.6% of EMP patients), radiation and chemotherapy (2.1%), surgery and chemotherapy (0.5%), surgery, chemotherapy and radiation (0.8%), and 2% patients received no therapy. In the non‐UAD area, chemotherapy was more common (16.2% of patients with EMP), followed by radiation and chemotherapy (4.9%), surgery and chemotherapy (4.9%), surgery, radiation and chemotherapy (1.2%), and 1.6% of patients received no therapy.

FIGURE 3

Outcomes in the patients with EMP dependent on therapy according to the literature search. Graph shows all patients for whom the outcomes were reported (n = 535), including those for whom no tumor localization was given. R, recurrence, MM, multiple myeloma.

FIGURE 4

Overall survival curve (Kaplan–Meier) of patients with extramedullary plasmacytoma in (A) the upper aero‐digestive tract (UAD) and (B) outside of the upper aero‐digestive area (non‐UAD) compared to treatment according to the literature search.