Teaching Case

A 39-year-old nulliparous woman in the 14^th week of gestation presented with abdominal pain, vomiting and fever. Physical examination was normal. She denied previous significant illnesses. Her family history was also unremarkable.

Initial vaginal ultrasound showed a viable pregnancy, ascitis and diffuse thickening of

the pelvic peritoneum. Abdominal ultrasound confirmed those findings and could not demonstrate any acute focal inflammatory condition explaining the patient’s symptoms.

As peritoneal carcinomatosis was suspected and the patient was pregnant, a T2-weighted whole-body MRI was used instead of a CT scan for initial tumour evaluation and staging. It showed moderate ascitis, diffuse peritoneal thickening, diffuse homogenous soft tissue infiltration along leaves of mesentery and enlarged ovaries.

No significant lymphadenopathy or other organs involvement were noted.

Fine-needle aspiration of the ascitic fluid showed multiple medium size blastic cells with

prominent cytoplasmic vacuoles and frequent mitosis consistent with Burkitt’s

lymphoma. The tumour was CD10+, CD20+ and Ki67 + (flow cytometry). Gene break

point on MYC (8q24) was determined by fluorescent in situ hybridisation.

Pregnancy was electively interrupted.

Posttreatment imaging showed complete remission of the lymphomatous involvement and normal-sized ovaries.

Burkitt's lymphoma (BL) is a highly aggressive germinal B-cell lymphoma characterised by a reciprocal chromosomal translocation (involving one of the Ig gene heavy or light chain loci on chromosomes 2, 14 or 22 and the proto-oncogene MYC on chromosome 8) (1), frequently presenting at extranodal sites and with extremely fast growth rate (doubling time of 24- 48 hours).

About 1/1000 women present neoplastic diseases during pregnancy (2): Lymphoma is the fourth most frequent tumour (after melanoma, breast and cervical cancer), with Hodgkin’s lymphoma being the most common and BL being extremely rare with only a few cases reported.

Three different variants of BL are known: (3) (4)

– Endemic (very common in Africa and Papua New Guinea): Strongly associated with Epstein-Barr virus (EBV) infection (95%) and with malaria and typically affecting children, 60% with facial bone involvement and 58% with abdominal involvement

– Sporadic: In 5-15% of the cases associated with EBV infection, 80% with abdominal involvement and 14% with mandible involvement.

– Immunodefficiency-related: Usually associated with HIV infection (45% coinfected with EBV) but also described in allograft recipients and congenital immunodeficiencies. The most common sites of involvement are distal ileum, cecum and mesentery

PET-CT is normally used for staging and follow-up but MRI is very useful in particular clinical settings like in our case.

The abdomen is the most common site of involvement, particularly the ileocecal region due to the high concentration of lymphoid tissue. BL of the bowel manifests as a focal mass or as segmental bowel thickening that can lead to aneurismal lumen dilatation and intussusception.

BL can also present as retroperitoneal and mesenteric nodes that often encase mesenteric vessels. In advanced cases lymphomatosis may be present but isolated involvement of the peritoneum is rare (5).

Although less common, solid organ involvement can appear as single or multiple solid masses or as infiltrative areas with or without visceromegaly.

Thoracic involvement can manifest as pleural effusion and lymphadenopathy. Focal masses affecting the pericardium, myocardium, lung, bronchial lumen, breasts and chest wall are less common.

Head and neck are the most common sites of involvement in the endemic form, presenting as a rapidly enlarging painless osteolytic jaw mass. Sporadic BL tends to present with nodal and Waldeyer ring involvement.

Central nervous system involvement is more common in the sporadic and immunodeficiency-related BL and can present anywhere along the neuroaxis as masses or leptomeningeal thickening.

Bone marrow involvement is often seen in the setting of bulky disease elsewhere and associates worse prognosis.

Aggressive chemotherapy is the mainstay of therapy. If pregnancy is not interrupted, alternative chemotherapy regimens with drugs potentially less harmful for the foetus are elective.

Written informed patient consent for publication has been obtained.