A rare case of renal medullary carcinoma without sickle cell hemoglobinopathy in a Japanese woman

Abstract

Diagnostic and treatment guidelines for renal medullary carcinoma are not established. A 52-year-old Japanese woman presented to her general physician with symptoms of cough and respiratory distress. A primary malignant tumor of the right kidney and multiple metastases were suspected during imaging; therefore, she was referred to our department for consultation. The results of a computed tomography-guided tumor biopsy revealed a diagnosis of renal medullary carcinoma without sickle cell hemoglobinopathy. This case was atypical because renal medullary carcinoma was not accompanied by sickle cell hemoglobinopathy and the patient was Japanese.

Highlights

•

RMC is a rare malignancy with a poor prognosis.
•

Guidelines for the diagnosis and treatment of RMC have not been established.
•

RMC affects men twice more than women and is common in the right kidney.
•

Most patients with RMC also have sickle cell hemoglobinopathy.
•

Sickle cell hemoglobinopathy is most commonly observed in sub-Saharan Africa.

1 Introduction

Renal medullary carcinoma (RMC) is a rare high-grade renal cell carcinoma with a poor prognosis. Guidelines for the diagnosis and treatment of RMC have not been established. The most common symptoms of RMC are gross hematuria, lateral abdominal pain, and an abdominal mass. . RMC affects men twice as frequently as it affects women, ^, , and it is commonly found in the right kidney; however, the reasons for these characteristics are unknown. ^, .

Most patients with RMC also have sickle cell hemoglobinopathy (SCH), , which is most commonly observed in sub-Saharan Africa; therefore, the prevalence of RMC is likely high in that same region. . RMC often exhibits early and extensive metastases, and most cases are diagnosed as metastatic tumors. . Treatment comprises radical nephrectomy for localized tumors after a response to systemic therapy is observed. . Although some platinum-based chemotherapy can effectively treat metastatic tumors for a short period, an effective treatment has not yet been established; therefore, enrollment in a clinical trial, if available, is recommended. .

We report a case of RMC without SCH in a Japanese woman.

2 Case report

A 52-year-old Japanese woman experienced respiratory discomfort and cough for several months. Because her symptoms did not improve, she presented to a local hospital. Computed tomography (CT) suggested multiple systemic metastases of right renal cell carcinoma; therefore, the axillary lymph node biopsy was performed, and she was referred to our department.

Although the blood biochemical test results revealed elevated levels of aspartate aminotransferase (to 137 IU/L) and alanine aminotransferase (to 166 IU/L) that were likely caused by liver metastasis, other remarkable findings were not observed. A pathological examination of lymph node biopsy specimens performed at the previous hospital showed an infiltration pattern and positivity for paired box 8, suggesting metastases of tumors arising from the Müllerian duct or renal cell carcinoma. Lymph node metastases of renal cell carcinoma were suspected because of negative estrogen receptor and progesterone receptor results.

CT revealed a tumorous lesion with irregular margins at the inferior pole of the right kidney ( Fig. 1 ). Positron emission tomography-CT revealed a mass in the right kidney and multiple metastases throughout the body ( Fig. 2 ).

When the patient presented to our department, the presumed condition was advanced renal cancer; therefore, we did not perform nephrectomy. Instead, we initiated drug therapy after the CT-guided biopsy results confirmed the histological type.

The patient’s general condition deteriorated 1 week after the biopsy was performed. Although the pathological diagnosis had not yet been confirmed, nivolumab treatment was administered. However, the patient’s general condition did not improve, and she died 1 week after treatment initiation.

Subsequently, the pathological diagnosis was confirmed, and the histological examination revealed an invasive renal tumor. Large tumor cells with papillary and tubular growth and large vacuolated and irregular nuclei were observed. Additionally, strong inflammatory cell infiltration in the stroma was observed without obvious sickle cell changes in the erythrocytes ( Fig. 3 ).