Presacral hematopoietic tissue: correlation of radionuclide and MRI findings

A systematic review of presacral extramedullary haematopoiesis: a diagnosis to be considered for presacral masses

AIM

Presacral masses are uncommon and have malignant potential; treatment typically includes surgical excision. However, there are conditions such as extramedullary haematopoiesis (EMH) which are benign. The present study aimed to summarize the presentation of presacral EMH in our institution, to review the literature and to offer management strategies for this rare condition.

METHOD

The literature was searched for articles related to presacral EMH, and case reports were collected from articles meeting the inclusion criteria. We collected data on patient demographics, diagnostic investigation, management and the results of treatment.

RESULTS

Thirty-nine patients were included in the systematic review. Initial imaging included computed tomography (CT), magnetic resonance imaging (MRI) or ultrasound (US) suggestive of EMH. Some patients then underwent a technetium scan (n = 7, 18%), biopsy of the presacral lesion (n = 27, 69%) or excision of the entire mass (n = 3, 8%). All patients who underwent technetium scan were confirmed to have EMH, demonstrating enhancement similar to bone marrow. Patients who underwent technetium scan and presacral mass biopsy had concordant results confirming presacral EMH (n = 5, 13%). Data on management were available for 35/39 (90%) with most patients followed by clinical observation (n = 20, 51%). Symptomatic patients were treated with radiotherapy (15%), surgical excision (15%) or hydroxyurea (5%) and blood transfusions (10%). Most (81%, n = 17/21) patients whose outcome was reported remained asymptomatic or experienced pain relief.

CONCLUSION

Although uncommon, EMH should be considered in the differential diagnosis of a presacral mass. Presacral EMH is a benign condition that can be suspected on CT or MRI and confirmed with technetium scan. Patients may not necessarily need to undergo biopsy to confirm haematopoietic elements. Unlike other presacral masses, patients diagnosed with presacral EMH can be managed by observation. If symptomatic, radiotherapy or surgical excision may be offered.

Presacral extramedullary hematopoiesis: an alternative hypothesis

Idiopathic extramedullary hematopoiesis (EMH) is the production of blood cells outside of the bone marrow without an underlying hematological pathology. This article examines the rare case of idiopathic EMH in the presacral area. A 65-year-old woman with a past medical history of a total abdominal hysterectomy and a negative hematological history presented with back and leg pain. MRI revealed a presacral mass. Fine needle aspiration revealed a diagnosis of EMH. The patient was managed conservatively with serial imaging. We present this patient with rare idiopathic, presacral EMH and review the literature on this topic. The current pathophysiology suggests that sacral fractures release hematopoietic stem cells, which in turn replicate to form an EMH mass. This review suggests a second mechanism in which surgical manipulation of the uterine tissue releases mesenchymal stem cells. These cells differentiate into stromal tissue that interacts with multipotent hematopoietic stem cells in order to form an EMH mass. Thus, idiopathic, presacral EMH may develop from either bone fractures or surgical manipulation of the uterus. Management of these patients should include watchful waiting unless intractable pain, new-onset weakness, or bowel/bladder dysfunction develops.

Extramedullary hematopoiesis in unusual locations in hematologically compromised and noncompromised patients

Extramedullary hematopoiesis (EMH) occurs as a compensatory reaction to an underlying hematologic abnormality. EMH is most commonly seen in the liver and spleen but rarely has been reported in other locations, as well. On rare occasions, EMH may mimic a neoplasm in hematologically noncompromised patients. In this report, we present three cases of EMH in unusual locations, two in the presacral soft tissue and one in the synovial lining of the knee joint. The patients with presacral masses had no hematologic abnormality. In all patients with EMH, imaging plays an important role in both localization of the lesion and guidance for the biopsy; when imaging results are correlated with histological findings, the diagnosis of EMH can be confirmed.

An interesting diagnosis for a presacral mass: case report

A presacral mass can present a diagnostic dilemma for the surgical oncologist. Differential diagnoses include congenital causes such as teratoma or chordoma, neurological causes such as neurilemoma or neurofibroma or other malignancies such as lymphoma or sarcoma. Diagnosis usually requires imaging such as CT and MRI and tissue biopsy. We present an unusual cause of a presacral mass being extramedullary haematopoiesis, found incidentally in a 71 year old female. Extramedullary haematopoiesis is defined as the production of myeloid and erythroid elements outside of the bone-marrow. This diagnosis is extremely rare in the presacral area especially in a patient with no haematological abnormalities. A review of the literature is presented.