Tumour-to-tumour metastasis: breast carcinoma to an olfactory neuroblastoma

Abstract

Tumour-to-tumour metastasis is a rare phenomenon. It occurs when a primary tumour is a recipient of a separate tumour within the same individual. We present a case of a 66-year-old woman with known breast cancer who presented with one-sided nasal symptoms. Examination and imaging revealed a unilateral polyp arising from the skull base. She underwent endoscopic polypectomy with the histology demonstrating tumour-to-tumour metastasis from a breast carcinoma to an olfactory neuroblastoma, a rare sinonasal tumour. Clinicians should be cautious of distant metastases in any patient presenting with head and neck symptoms and a known primary tumour. This is the first documented case of this type.

Background

Tumour-to-tumour metastasis is a rare phenomenon. It occurs when a primary tumour is a recipient of a separate tumour within the same individual. The most common donor malignant tumours are lung and breast. Renal-cell carcinomas are the most common recipient of tumour-to-tumour metastasis. We present a case of tumour-to-tumour metastasis from a breast carcinoma to an olfactory neuroblastoma, a rare sinonasal tumour. This is the first documented case of this type.

Case history

A 66-year-old woman was referred to the ear, nose and throat department with a six-month history of right nasal obstruction and occasional clear nasal discharge. She reported a diminished sense of smell for a number of years but did not complain of any facial pain or bleeding. Previous treatment with intranasal steroid drops had provided little improvement in her symptoms.

Her past medical history included bilateral breast cancer for which she completed neoadjuvant chemotherapy and a bilateral mastectomy ten years ago. Pathology from the specimens found invasive ductal carcinoma in the left breast and invasive lobular carcinoma in the right breast. This was followed by five years of tamoxifen therapy. Two years later, she was diagnosed with metastatic disease to the liver and bone and commenced on palliative chemotherapy with capecitabine and bisphosphonates. She has been under regular review by the oncology team since and her disease has remained stable.

Examination with flexible nasoendoscopy revealed a large erythematous polyp in the right nasal cavity. A computed tomography (CT) scan of the sinuses was performed and demonstrated a polyp arising from the skull base (Fig 1). As a result, she underwent an endoscopic right nasal polypectomy (Fig 2).

Figure 1.

Computed tomography (coronal) of the sinuses showing a large right polypoidal mass arising from skull base.

Figure 2.

a) Large polyp in right superior nasal cavity b) Partial dissection of polyp in right nasal cavity.

Immunohistochemistry performed on the nasal polyp showed a main tumour and an additional second population of malignant cells. The main tumour was formed of sheets and nests of cells, separated by vascular stroma. The cells were hyperchromatic with minimal cytoplasm, and the nuclei showed stippled chromatin. These malignant cells stained for Synaptophysin and S-100. There was negative staining for CD99, CAM5.2, CK5/6, CK7, CK20, TTF1 and p63. Within the main tumour, a second population of malignant cells was identified. These cells were seen singly and forming small lobules. They had round nuclei with eosinophilic cytoplasm. The cells were positive for ER (8/8), PR (8/8), CAM5.2, CK7 and GATA3. They were negative for HER2 (4b5) and E-cadherin. They showed granular cytoplasmic staining for p120. The histological and immunohistochemical features represent an incidental olfactory neuroblastoma with a foci of metastatic lobular carcinoma of breast.

Postoperatively, her symptoms of nasal obstruction and anosmia were resolved and repeat CT and magnetic resonance imaging (MRI) of the sinuses showed no residual disease (Fig 3). The case was discussed at a multidisciplinary team meeting and she was restarted on capecitabine. She remains under regular oncological follow-up.

Figure 3.

a) Postoperative computed tomography (coronal) and b) magnetic resonance imaging (axial) with well-aerated nasal cavities and no evidence of residual nasal mass.

Discussion

Olfactory neuroblastoma, or aesthesioneuroblastoma, is a rare sinonasal tumour that was first described by Berger et al in 1924.¹ It accounts for 2% of nasal tract and sinus neoplasms. It is thought to arise from olfactory neuroepithelium located in the upper part of the septum, cribriform plate and superior turbinate.² Typical symptoms include nasal obstruction and epistaxis with anosmia being less common. As they are slow-growing tumours, diagnosis is usually late or when the tumour has grown large enough to cause significant symptoms.

In the case of our patient, after reviewing her staging head CT following the initial diagnosis of breast cancer 10 years `ago, a right unilateral nasal polyp can be seen (Fig 4). We suspect this may be the olfactory neuroblastoma. Surprisingly, there has been minimal growth in the interim period. There is currently no literature available on conservative monitoring so we are unable to compare this growth to other cases. However, it is thought that well-differentiated tumours are linked with a less aggressive, slower progression and a reduced chance of local recurrence.³

Figure 4.

Computed tomography (axial) taken 10 years prior to nasal symptoms during breast cancer staging.

Breast cancer is the most common cancer found in women globally and the second most common overall. It metastasises most often to bone, lungs, regional lymph nodes, liver and brain. It can also spread to the head and neck region.⁴ Although distant metastases to this area are rare, breast cancer has been found in almost all of the head and neck subsites and is one of the more common tumours to metastasise to the orbit, sinonasal tract, cervical lymph nodes, temporal bone and mandible.⁵

The most frequently occurring metastases to the nasal cavity and paranasal sinuses are from renal cell carcinoma. Prostate, breast, thyroid and gynaecological cancer have also been found. The maxillary sinus is most likely to be affected and metastases are often associated with disseminated disease and a poorer prognosis. The cause of cancer cells reaching this area is thought to be from haematogenous spread via the vertebral venous plexus or lymphogenous spread via retrograde flow from the thoracic duct. Symptoms often mimic those of a primary tumour, including unilateral nasal obstruction, epistasis, facial pain and nasal discharge.⁶

Metastases to the head and neck can be the first manifestation of any malignancy in up to 35% of patients.⁷ This was found in a case series by Gondim et al.⁵ Three (12%) of their 25 patients with metastatic breast cancer had their first diagnostic specimen from the head and neck. Interestingly, the case series also showed that 16 (80%) patients presented with their head and neck metastases five years after their original diagnosis. The mean interval period was 10.9 years. This is a similar time frame to our patient who was initially diagnosed 10 years ago.

Tumour-to-tumour metastasis is a well-documented but uncommon entity. Diagnostic criteria were set out by Campbell et al and include: 1) the presence of at least two primary tumours; 2) the receiving tumour must be a true benign or malignant neoplasm; 3) the metastatic neoplasm shows established growth in a recipient tumour and not the result of contiguous growth from an adjacent tumour or tumour cell emboli; and 4) where lymphoreticular malignant tumours are already present, tumours that have metastasised to lymph nodes should be excluded.^8,9 Our patient fulfilled all of these criteria.

The most common recipient tumour from tumour-to-tumour metastasis is renal cell carcinoma. Nonetheless, the receiving tumour most recorded to host breast cancer is a meningioma. This association is thought to be related to the significant amount of progesterone and oestrogen receptors found in each tumour.¹⁰

The prognosis for patients with breast metastases to the head and neck is usually poor as it is often associated with disseminated disease. However, breast cancer progression can be gradual, and the introduction of more effective and targeted treatments for women with distant metastases has helped to slow the progression so that patients live longer.

Conclusion

Clinicians should be cautious of distant metastases in any patient presenting with head and neck symptoms and a known primary tumour. Tumour-to-tumour metastasis is uncommon but can occur in patients several years after initial diagnosis of their primary tumour. It is essential a multidisciplinary team approach is used to tackle the management of such patients as curative treatment may not be possible.