Bone marrow metastases of solid tumors – microscopic images

Introduction

Metastatic cancers represent a challenge to clinicians, particularly in the case of bone marrow metastasis. Most common cancers that associate medullar metastases are breast, prostate, neuroblastoma, gastric, lung, and colorectal cancers^(1,2).

The management of cancer is influenced by the presence of bone marrow metastases, making it crucial to assess the patient’s status thoroughly. Bone marrow metastases should be suspected when clinical and biological changes indicate their possibility. The most frequent hematological abnormalities are anemia, leucoerythroblastic reactions, and thrombocytopenia⁽¹⁾. The patients often complain of bone pain, symptoms related to anemia, and weight loss^(2,3). The workup for confirmation should include imaging studies and bone marrow biopsy or aspiration. To establish the origin of the abnormal cells, histopathological and immunohistochemical exams should be performed⁽²⁾.

The prognosis for cancer patients with bone marrow metastases is poor, with a median survival of three months⁽⁴⁾. However, patients eligible for systemic chemotherapy may have a slightly better outlook, with a median survival of nine months, compared to those who receive only best supportive care, which typically results in a median survival of one month⁽⁴⁾. Due to myelosuppression, the patients are more susceptible to complications from cytopenia, and the chemotherapy doses need to be reduced. Additionally, the presence of bone marrow metastases indicates advanced disease⁽²⁾.

We present the cases of two patients with solid tumors and bone marrow metastases.

Case 1

A 54-year-old woman was diagnosed with breast cancer in 2018, for which she underwent a mastectomy followed by chemotherapy, radiotherapy, and hormonal therapy. In 2023, she had a second mastectomy, with histopathological and immunohistochemical examinations returning normal results. However, a follow-up CT scan in 2024 revealed multiple bone lesions in the skull, lumbar spine and lateral ribcage, some of which interrupted the cortical bone, and others caused pathological fractures, but there were no signs of breast cancer recurrence. Her complete blood counts and biochemistry studies were normal. The bone marrow aspirate showed cohesive clusters of neoplastic cells (Figure 1).

Case 2

A 77-year-old patient was diagnosed with prostate adenocarcinoma in 2019, and subsequently received immunotherapy and radiation treatment. Four years later, he developed moderate anemia with a hemoglobin level of 8 g/dl and leukopenia with a white blood cell count of 3000/mm³. The peripheral blood smear showed an increased left shift in the differential WBC (white blood cell) count and erythroblastosis. The bone marrow biopsy revealed infiltration by neoplastic cells (Figure 2), without any signs of hematological disease.

Discussion

Bone marrow metastasis may manifest as the initial presentation of an occult cancer, occur concurrently with other tumors, or emerge during follow-up⁽⁵⁾. Additionally, in rare instances, bone marrow metastases can serve as the sole evidence of cancer⁽⁶⁾.

Our cases highlight the diverse presentation of bone marrow metastases. In the first case, there were no clinical or laboratory indications of bone marrow involvement, and breast cancer was in remission. The imaging studies showing bone lyses could potentially be attributed to other conditions, such as multiple myeloma. On the contrary, the second patient demonstrated a more typical presentation, with evident disease progression and cytopenia.

Conclusions

Bone marrow evaluation should be considered in patients with solid tumors and unexplained blood abnormalities. A thorough investigation is essential to establish the diagnosis, as it significantly impacts both treatment decisions and prognosis.   

Corresponding author: Ana-Maria Vlădăreanu E-mail: vladareanuanamaria@yahoo.com

Conflict of interest: none declared.

Financial support: none declared.

This work is permanently accessible online free of charge and published under the CC-BY licence.