Renal extramedullary haematopoiesis mimicking renal lymphoma on computed tomography

Paratesticular Extramedullary Hematopoiesis in Children

CONTEXT.—

Extramedullary hematopoiesis (EMH) is an uncommon occurrence, usually associated with hematologic disorders, but it rarely presents as an isolated finding.

OBJECTIVE.—

To determine the frequency, immunomorphologic features, and clinicopathologic background of EMH in orchiectomies from pediatric patients.

DESIGN.—

All orchiectomy specimens removed from children from 2008 to 2020 in our institution were retrospectively reviewed. Biopsies and neoplasias were excluded. The EMH diagnosis was rendered when hematopoietic cell precursors were present. Immunohistochemical stainings were performed to characterize the hematopoietic components.

RESULTS.—

Seventy-nine orchiectomies from 77 children (mean age, 5 years; range, 0-17 years) were included in our study. Forty-three patients (55.8%) underwent surgery for testicular atrophy, 30 (39.0%) for torsion, and 4 (5.2%) for intersex conditions. EMH was identified in 6 of 79 orchiectomies (7.6%), all performed for testicular torsion. All patients but one were newborns, and the remaining patient was 15 years old. No patient had evidence of a hematologic disorder. All EMH foci were in a background of reactive changes with a variable extension, either in the epididymis (4 cases) or in the deferens duct (2 cases). Immunostaining confirmed an association of myeloid (myeloperoxidase+) and erythroid precursors (E-cadherin+) in all 6 cases. One case also presented rare megakaryocytes, and one showed benign TdT+ B-cell precursors.

CONCLUSIONS.—

To our knowledge, this is the first study that demonstrates EMH as a common finding in orchiectomy samples, especially from newborns. Despite the lack of pathologic potential, it is important to recognize EMH in order to avoid misdiagnosis.

Case 237: Renal Cell Carcinoma with Osseous Metaplasia

History A 47-year-old man presented with palpitations and decreased exercise tolerance. A peripheral blood smear revealed anemia, thrombocytopenia, and blast cells, and a diagnosis of acute myeloid leukemia was made. Immunohistochemistry revealed positivity for cluster of differentiation (or CD) markers, which have been reported to be associated with an increased risk of extramedullary leukemic involvement. Thus, contrast material-enhanced computed tomography (CT) of the thorax, abdomen, and pelvis was requested to enable exclusion of any extramedullary extension of leukemia. Unenhanced and contrast-enhanced nephrographic phase CT was performed. Follow-up CT 3 months later showed minimal interval change in the lesion (images not shown).

The renal sinus--transitional cell carcinoma and its mimickers on computed tomography

The renal sinus is a deep recess located at the medial aspect of the kidney surrounded by the renal parenchyma. It contains within it the collecting system of the kidney, lymphatics, nerves, and renal blood vessels. The remainder of the sinus is filled with adipose and fibrous tissue. A variety of pathological conditions arise from the different tissues in this site. The aim of this review is to explore and illustrate the common and less common processes affecting the renal pelvis.

Imaging of primary and secondary renal lymphoma

OBJECTIVE

This article reviews the CT and MRI patterns of primary and secondary renal lymphomas and discusses the role of percutaneous biopsy in diagnosis and management.

CONCLUSION

Renal lymphoma has a variable imaging spectrum and may mimic renal cell carcinoma. An awareness of the typical and atypical imaging features of both primary and secondary renal lymphomas can help the radiologist to suggest these diagnoses and recommend biopsy when appropriate.

Contrast-enhanced ultrasound findings in a case of renal extramedullary hematopoiesis

We present the case of an 80-year-old man with two renal solid masses found at sonography, which were imaged by contrast-enhanced ultrasound, CT, and MRI and confirmed histologically. Contrast-enhanced ultrasound findings suggested a benign mass and a CT-guided biopsy yielded a diagnosis of extramedullary hematopoiesis.

Extramedullary haematopoiesis in the kidney

Extramedullary haematopoiesis (EMH) is the development of haematopoietic tissue outside the bone marrow and it most often occurs in the liver and spleen. Renal EMH is quite rare and there are very few case reports concerning the kidney. We describe two cases of ‘renal histologically documented EMH’ and, in particular, in the second of these two, the EMH tissue coexists with a clear cell renal carcinoma. Although rare, these clinical pictures raise some questions about the role of needle biopsy in the management of renal masses that present a diagnostic dilemma, especially in cases without involvement of other abdominal or intrathoracic organs.