Chloroma of the testis in a patient with a history of acute myeloid leukemia.

Chloroma, or granulocytic sarcoma, is a rare extramedullary solid hematologic cancer, found concomitant with acute myeloid leukemia. It is infrequently associated with other myeloproliferative disorders or chronic myelogenous leukemia. Chloroma of the testis after allogeneic bone marrow transplantation is particularly sparsely represented in the literature. It is suggested that an appropriate panel of marker studies be performed along with clinical correlation and circumspection to avoid misleading conclusions. We report an interesting case of a 32-year-old male with a clinical history of acute myelogenous leukemia, postallogeneic peripheral blood stem cell transplantation that was found to have chloroma of the right testis.

INTRODUCTION

Chloroma is a rare extramedullary neoplasm composed of immature myeloid cells (myeloid sarcoma)[1] presenting as single or multiple masses.[2] It would affect both sexes equally,[2] children more commonly than adults and 60% of the patients are younger than 15-year-old.[3] Myeloid sarcomas are associated with acute myeloid leukemia (AML) in 2%–8% of the cases, especially in situations of cytogenetic abnormalities such as t, inv, and 11q23.[456] The testicles are considered to be an uncommon site for myeloid sarcomas,[78] and there are a few cases with localization of chloroma in one of the testes.[9] Hereby, we would report an extremely rare case of chloroma of the testis in a patient with a history of AML.

CASE REPORT

In the March of 2015, a 32-year-old man in Isfahan, Iran, had a history of AML sought care because of a painless right testicular mass. The AML, that was diagnosed 6 years earlier, was classified as M4 using the French–American–British system. The patient had received aggressive chemotherapy with multiple episodes of relapse and eventually underwent allogeneic peripheral blood stem cell transplantation 5 years ago. The testicular mass was detected 45 months after transplantation. The right testicular ultrasound showed two masses, 1.7 cm × 1.1 cm and 2.2 × 1.5, with increased blood flow. Then, the right orchiectomy was performed. No cytogenetic analysis was performed.

Macroscopic anatomopathological study of a sample from the right orchiectomy revealed two 1.7 and 2.2 cm masses with creamy color, relatively firm and solid sectional surface, placed at the outer half of the testis.

Histopathologic examination showed diffuse infiltration of immature monotonous large hyperchromatic neoplastic cells with scanty cytoplasm and round-to-oval nuclei [Figure 1].

Figure 1

Histology shows diffuse infiltration of immature monotonous large hyperchromatic neoplastic cells with scanty cytoplasm (H and E, ×400)

Immunohistochemical studies consistently manifested the expression of leukocyte common antigen, BCL2, CD117, CD68 (focally), and Ki67 index about 60%, [Figures 2–6] but the expression of cytokeratin, placental alkaline phosphatase, CD10, CD3, CD20, CD3O, CD34, and ALK1 was negative and the diagnosis of granulocytic sarcoma was established. No cytogenetic analysis was performed. Afterward, patient's chemotherapy (cytarabine and hydroxyurea) was started, and now, he is well.

Figure 2

Immunohistochemistry shows positivity for leukocyte common antigen

Figure 6

Ki67 index is about 60% of neoplastic cells (×400)

Immunohistochemistry shows positivity for CD117

Immunohistochemistry shows positivity for BCL2

DISCUSSION

Chloroma usually occurs as a secondary manifestation either before or simultaneously with AML.[2] Less frequently, it may appear after complete hematologic remission,[10] which strongly indicates bone marrow or other extramedullary relapses.[10] It has also been observed as a primary chloroma which precedes AML by months or years[31112] or it can be an independent entity, without progression to a hematologic disease.[713] Chloroma may also appear as a relapse in patients with a history of chronic myeloid leukemia (CML) after allogeneic peripheral blood stem cell transplantation and subsequent complete hematologic remission.[14] GS affects 2.5%–9.1% of the patients with AML[2] and 4.5% of those with CML.[15]

The most affected sites are bone structures (cranium, paranasal sinuses, sternum, ribs, vertebrae, and pelvis), central nervous system, soft tissues of the head and neck (especially the orbit), skin, lymph nodes, and breasts.[1617] Initial presentation of AML with involvement of the testicles, as described in the present case, is considered to be uncommon, with a poor prognosis.[818] The correct histological diagnosis is based on identifying the granulocytic characteristics in the neoplastic cells. Because of high morphological variability and possible nonidentification of myeloid differentiation (variable), errors may occur especially when the neoplasia presents minimal myeloid differentiation such that it is composed of poorly differentiated cells distinct from the myeloblasts that are found in the bone marrow in cases of concomitant AML.[519]

Immunohistochemistry is of great value in identifying antigens associated with the myeloid lineage (CD13, CD33, CD43, CD117, lysozyme, and CD68). In the current case, the neoplasia showed positive reaction for CD68, which is the most commonly expressed markers of myeloid differentiation.[620]

CONCLUSION

Despite the rarity of myeloid sarcoma, it should be taken into consideration in the differential diagnoses of undifferentiated neoplasia, with proper use of immunohistochemical techniques to make a rapid diagnosis and start treatment, regardless of the unsatisfactory response with frequent relapses, and evolution to acute leukemia.

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Conflicts of interest

There are no conflicts of interest.