Discussion:
In the autopsy of patients with breast cancer, the risk of spleen
involvement has been 11-17%, which is uncommon compared to metastasis
to other organs. In contrast, the most common organ of metastasis is the
lung with a risk of 57-77% (4).
In the study by Corinna in the autopsy of patients with cancer,
metastasis to the spleen has been more common among younger patients and
in those with more sites of metastasis (2), while in our case, the
spleen has been the only site of metastasis.
Metastasis to the spleen occurs in a delayed way and rarely becomes
symptomatic; thus it is seldom diagnosed by the physician (5). However,
in our case, metastasis to the spleen was early and synchronous with the
primary breast cancer as well as symptomatic with splenomegaly
presentation. Various etiologies have been propounded for splenomegaly,
including hepatic diseases, malignancies including lymphoma and
leukemia, splenic vein thrombosis, cytopenia (which causes functional
splenomegaly), infections, splenic sequestration, connective tissues
disease, and focal lesions such as hemangioma, abscesses, cysts, and
metastasis (3).
For diagnosis of splenomegaly, a CT scan and sonography can be used.
MRI, PET scan, biopsy, splenectomy, and liver-spleen colloid scanning
are recommended in special cases (3).
In two cases reported by Cummings et al., the primary symptoms of
patients who had metastasis to the spleen were ITP (due to diffuse
splenic metastases), and the absence of any specific tumors in the
imaging complicates the diagnosis. In these two cases, the patients had
also metastases to the bone, and the spleen metastasis was delayed (6).
In the literature review, there are sparse studies on metastasis to the
spleen with breast origin, and most metastases are multiple as well as
multiorgan. In the study by Bartolotti, one case of breast cancer who
had metastasis to the lymph node, lungs, and vertebrates at the time of
diagnosis experienced a relapse in the spleen after four years; in the
CT scan, it was in the form of two focal lesions and was diagnosed with
FNA. The patient underwent chemotherapy (7).
Nevertheless, regarding solitary metastasis to the spleen with breast
origin, we found only five case reports in the literature, which were as
follows:
The first case was found in 2001; a breast cancer who experienced
solitary metastasis to the spleen after 9 years (8).
S IYPE Case in 2002; she was a 54-year-old woman who found solitary
metastasis to the spleen after 2 years, and underwent splenectomy (9).
Kari Sufficool et al. in 2012 reported synchronous metastasis to the
spleen with breast origin diagnosed through FNA (10).
In 2013, a woman with breast cancer was reported; after the treatment
and in the follow-up was examined due to abdominal pain and fever, for
whom metastasis to the spleen was diagnosed. She passed away 3 months
after due to unknown reasons (11).
In 2019, Sohaila Fatima et al. reported a 62-year-old breast cancer case
(ILC) with synchronous solitary metastasis to the spleen, who underwent
chemotherapy (12).
A case of hairy cell leukemia and breast cancer have been reported in
2013. The patient was a 65-year-old woman with the diagnosis of breast
cancer who was treated with surgery and chemotherapy. About 20 years
later, hairy cell leukemia was confirmed by cytopenia in the complete
blood count and BMB(13).
This case has been reported considering the uncommonness of solitary
metastasis to the spleen from breast cancer origin as well as
synchronous hairy cell leukemia.