Contributed by Rebecca Ocque, MD and Sarah Navina, MDDIAGNOSIS
METASTATIC LOBULAR BREAST CARCINOMA
FOLLOW-UP
Thereafter, she had a mammogram and ultrasound of breast that showed five hypoechoic irregular lesions within the right breast, two enlarged right axillary lymph nodes, and right skin thickening. Ultrasound guided biopsy demonstrated invasive mammary carcinoma consistent with lobular breast cancer.
DISCUSSION
The frequency of metastasis of carcinoma to the orbit and eye has been difficult to quantify, ranging from 0.5 to as high as 12% (Ferry and Font, 1974; Wickremasinghe et al., 2007). This discrepancy is likely due to the differences in the patient population studied (patients with widely metastatic disease verses asymptomatic patients with malignant tumors) and how the diagnosis was made (clinical eye examination verses pathological diagnosis after death). Metastasis to the eye (uveal metastasis) is more common than the orbit or periorbital structures (Shields et al, 1997). Breast cancer metastasis is the most common type of carcinoma metastasis to the eye and orbital structures (Mehdi and Bita, 2007). However, metastasis to the orbital structures is still rare (Wickremasinghe et al., 2007).
Invasive lobular breast cancer (ILC) is the second most common invasive breast cancer second to invasive ductal adenocarcinoma, accounting for between 5-15% of all invasive breast cancers (Rosen, 2001; Cibas and Ducatman, 2009). The tumor cells arise from the lobules of the breast. ILC tumors are often multicentric and poorly delimited (Tavassoli and Devilee, 2003). Multiple patterns of ILC are recognized with the classical variant being the most common. The classical pattern is characterized on surgical specimens by small, bland, discohesive cells which are arranged individually within the fibrous connective tissue or arranged in single file rows invading through the stroma. Very little host reaction or disturbance of the background stroma is appreciated and very few mitosis are seen. The tumor cytology is characteristically bland: small cells with round to notched ovoid nuclei with a thin rim of cytoplasm and occasional cells containing a central mucoid vacuole. The pleomorphic variant has a greater degree of cellular atypia and pleomorphism with cells demonstrating occasional apocrine, histiocytoid, and plasmacytoid cytology. ILC is typically positive for estrogen receptor (70-95% of cases) and progesterone receptor (60-70%).
Because the tumor cytology is usually bland with few to any mitotic figures, ILC metastasis to fluids is notoriously difficult to detect. As discussed previously, the cells typically are small and round with occasional cells having plasmacytoid or histiocytic changes. Therefore, the carcinoma can resemble mesothelial cells, histocytes, and lymphocytes in fluid cytology (Cibas and Ducatman, 2009). In light of the bland and deceptive cytology, much care must be made not to call these specimens negative. Immunohistochemical stains are routinely required to make a definitive diagnosis of metastasis. Cibas advocates that every effusion from a patient with known ILC be stained for appropriate immunohistochemical markers (Cibas and Ducatman, 2009).
This case is an excellent example of the importance of incorporating clinical information with multiple pathological samples. Initially, the clinical suspicion was for an inflammatory lesion. The orbital biopsy was diagnostic for invasive lobular breast cancer. The cytology of the ascites fluid was deceptively normal with a relative polymorphous population of inflammatory cells, mesothelial cells, and bland tumor cells that were really only evident after immunohistochemical staining. This cytology sample may have been seen as essentially normal had the index of suspicion for carcinoma not been high.
REFERENCES
Ahmad SM, Esmaeli B. Metastatic tumors of the orbit and ocular adnexa. Current Opinion in Ophthalmology, 2007:405-413.
Cibas ES, Ducatman BS. Cytology: Diagnostic Principles and Clinical Correlates. Philadelphia: Saunders Elsevier, 2009:145, 239-240.
Ferry AP and Font RL. Carcinoma Metastatic to the Eye and Orbit: A Clinicopathologic Study of 227 Cases. Archives of Ophthalmology , 1974; 92: 276-286.
Rosen PP. Invasive lobular carcinoma. Rosen's Breast Pathology. Philadelphia: Lippincott Williams & Wilkins, 2001:627-52.
Shields CL, Shields JA, Gross NE, Schwartz GP, Lally SE. Survey of 520 uveal metastases. Ophthalmology 1997; 104:1265-1276.
Tavassoli FA and Devilee P. World Health Organization Classification of Tumours: Tumours of the Breast and Female Genital Organs. Lyon: IARC Press, 2003: 23-26.
Wickremasinghe S, Dansingani KK, Tranos P, Liylanage S, Jones A, Davey C. Ocular presentations of breast cancer. Acta Ophthalmologica Scandinavica 2007; 85:133-142.
Contributed by Rebecca Ocque, MD and Sarah Navina, MD
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