Key-words:
Extramedullary plasmacytoma - extramedullary plasmacytoma - ovary - plasmacytoma -
primary neoplasm
Introduction
Plasmacytomas are a group of neoplasms characterized by the proliferation of mature
plasma cells, typically synthesizing monoclonal immunoglobulins.[[1]] They exist in three clinical forms: multiple myeloma (MM), medullary plasmacytoma
(MP), and extra MP (EMP). Occasionally, plasmacytomas may present as solitary lesions
in the bone marrow known as solitary intra MPs. In 5%–10% of reported solitary plasmacytomas,
the lesions may be found outside the bone marrow and are named solitary EMPs.[[2]]
Voigt reported the first case of EMP in 1938,[[3]] but half of the reported cases have been published in the past 8 years [[Table 1]],[[2]],[[3]],[[4]],[[5]],[[6]],[[7]],[[8]],[[9]],[[10]],[[11]],[[12]],[[13]],[[14]] potentially indicating greater detection or incidence. EMP is a rare primary soft-tissue
plasma cell tumor commonly found in the head and neck, with 90% occurring in the upper
aerodigestive tract.[[12]],[[15]] EMP typically affects middle-aged persons (55–60 years; male: female ratio of 3:1).
Confirmed risk factors for EMP remain unknown, but prior radiation exposure has been
suggested. These patients have a higher rate of progression to MM/disseminated disease,
and they require close monitoring after appropriate treatment.[[12]] Ovarian plasmacytomas are unique and have an unusual presentation.[[9]],[[11]],[[13]]
Table 1: Published cases of ovarian plasmacytoma (chronological order)
Case Report
In January 2016, a multiparous Libyan woman aged 42 years presented at the Department
of Medicine, Tripoli Central Hospital, Tripoli, Libya, with abdominal distension of
7-day duration. Her workup included ultrasound examination, which revealed marked
ascites and a left ovarian mass measuring 6.5 cm × 8 cm. Blood investigations revealed
CA 125 of 1602 U/ml, mild iron deficiency anemia with Hgb 10.4 g/dl Vitamin D deficiency.
Anti-HIV, anti-HCV, and Anti-HbsAg antibodies were negative.
Abdominal and pelvis with intravenous contrast [[Figure 1]] revealed a left ovarian mass measuring 9 cm × 8.7 cm, with a cystic part and a
contrast-enhanced solid part, with marked ascites in the abdomen and pelvis. She underwent
a transabdominal hysterectomy and bilateral salpingo-oophorectomy. The patient did
not require chemotherapy or radiotherapy postoperatively, and 6-month follow-up was
uneventful.
Figure 1: Computed tomography scan abdomen and pelvis. Evidence of sizeable mixed density mass
measuring about 9 cm ˟ 8.9 cm, arising from the left ovary, showing cystic par and
contrast enhancement solid part. Marked ascites fluid is seen in the abdominal and
pelvic cavity
The ovarian mass had a smooth outer surface and measured 18 cm × 8 cm × 5 cm. Serial
sections of the mass showed a grayish-brown solid surface with some cystic changes.
Histopathological examination shows diffuse sheets of plasma cell infiltration replacing
all ovarian stroma [[Figure 2]]. The plasma cells are characterized by eccentrically located nuclei and bright
eosinophilic cytoplasm with high mitotic figures. Many multinucleated cell forms are
seen. Histopathologic examination showed no evidence of malignancy in the omentum
or ascitic fluid.
Figure 2: Histopathologic photo of varian plasmacytoma: Diffuse sheet of plasma cells infiltration
replacing all ovarian stroma, the plasma cells characterized by eccentrically located
nuclei, and bright eosinophilic cytoplasm. Many multinucleated cell forms are seen
Immunohistochemical analysis showed that the plasma cells were positive for CD138
and leukocyte common antigen, with kappa light chain restriction and faint focal positivity
for CD79a. The results were negative for CD20, CD3, myeloperoxidase (MPO), placental
alkaline phosphatase (PLAP), inhibin, CK, and CD68. The proliferative index for Ki67
was high (40%). The workup for MM was negative.
The bone marrow biopsy shows bone trabeculae surrounding normocellular marrow spaces
containing trilineage hematopoietic elements admixed with scattered single plasma
cells and small clusters of plasma cell (<10% of the whole cellularity). Immunohistochemical
examination showed that the plasma cells were positive for CD138 with no restriction
to kappa or lambda light chains (positive for both kappa and lambda) and reactive
marrow with no evidence of monoclonal plasma cell infiltration.
In March 2016, the patient underwent a whole-body positron emission tomography/computed
tomography (PET/CT) scan, which revealed no pathological F18-fluorodeoxyglucose uptake
(neither focal nor diffuse), suggesting active malignancy. Postoperatively, CA 125
was 132.0 U/ml (February 10, 2016), and in October 2016, it was reduced to 20.8 U/ml
(within normal limits).
Discussion
Plasmacytoma develops from clonal proliferation of plasma cells identical to plasma
cells of MM both cytologically and immunophenotypically. EMP is a rare primary soft-tissue
plasmacytoma, representing <5% of all plasma cell tumors. These tumors generally remain
localized and are more responsive to therapy.[[11]]
Diagnosis of a solitary EMP requires the exclusion of MM. This distinction is important
since more than 60% of patients treated for a solitary plasmacytoma are cured with
only local therapies. In comparison, the 5-year survival of patients with MM is about
35%. The criteria for diagnosing solitary EMP include (a) histologically confirmed
solitary plasma cell lesion, (b) <10% plasma cells with no dyscrasia in bone marrow
biopsy of a distant site, (c) absence of end-organ damage such as those found in MM,
and (d) a full-body skeletal survey to exclude intramedullary disease. In solitary
EMP, aside from the possible occurrence of monoclonal gammopathies, all laboratory
values are expected to be normal. These include beta 2-immunoglobulin, blood counts,
electrolytes, serum-free light chains, and serum protein electrophoresis.[[2]],[[12]] Unlike MM, EMP usually does not exhibit serum M protein or Bence Jones light chains
in urine. Nevertheless, EMP may show M protein in up to 25% of cases. In our case,
neither M protein nor Bence Jones protein was present.[[12]]
Review of the literature review shows that most of the women present with a mass and
pain in the abdomen [[Table 1]]. Ovarian plasmacytoma is usually large at the time of presentation and more likely
to be on the left side.[[9]],[[12]] Shakuntala et al. reported an ovarian plasmacytoma presented as a large (15 cm
× 15 cm) right adnexal mass.[[11]] Cardenas-Perilla et al. reported the detection of bilateral ovarian plasmacytoma
by PET/CT 2 years after her treatment for EMP in the left femur.[[14]] All reported cases were either solid cystic or solid mass, except for the case
reported by Zhong et al., who reported a case with intraperitoneal hemorrhage (ovarian
rupture).[[10]] Ovarian EMP has been observed in elderly persons but only one child (12 years).[[8]]
Conclusions
The ovarian plasmacytoma is a rare tumor with information known about it. It is possible
to be present in women with abdominal masses with or without ascites. Adjuvant therapy
for ovarian plasmacytomas has not been established. If complete surgical resection
is achieved and there is no evidence of MM, a strategy of observation only should
be considered.
Authors' contributions
All authors were involved in the investigation of the reported case and drafting and
revising the case report.
Compliance with ethical principles
No prior ethical approval is required for single case reports and small case series
provided patient consent is obtained and all data are presented anonymously.
Reviewers:
Mx. Keng-Fu Hsu (Tainan, Taiwan)
Ahmed AbdelWarith (Riyadh, Saudi Arabia)
Hemali Heidi Sinha (Patna, India)
Editors:
Salem A Beshyah (Abu Dhabi, UAE)
