Invasive Lobular Carcinoma with Extracellular Mucin Production: Description of a Case and Review of the Literature

Abstract

Invasive lobular carcinoma of the breast is the second most common subtype of breast carcinoma. It accounts for 5-15% of the breast carcinoma cases reported. It shows a different metastatic pattern compared to invasive carcinoma of no special type. There are several variants of this cancer including the classic, solid, signet ring cell, tubulolobular, alveolar, trabecular, pleomorphic, and mixed subtypes each one with a distinctive morphology. Invasive lobular carcinoma has been associated with intracellular mucin production, in the form of intracytoplasmic lumina and signet ring cells whereas extracellular mucin production has been related to carcinomas of ductal origin. A new variant that displays extracellular mucin production was described recently. Only nineteen cases of this rare entity have been reported to date. In this manuscript, we report an additional case of invasive lobular carcinoma with extracellular mucin production, describing its clinico-pathological characteristics, and review the literature on the same.

Metaplastic Matrix-Producing Carcinoma and Apocrine Lobular Carcinoma In Situ Associated with Microglandular Adenosis: A Unique Case Report

“…It is characterized by invasive carcinoma transitioning directly to a cartilaginous and/or osseous stromal matrix lacking an intervening spindle cell component [ 22 ]. Its differential diagnosis includes invasive breast carcinoma with a large central acellular zone, spindle cell carcinoma, primary or secondary chondrosarcoma, malignant phyllodes tumor with heterologous (chondrosarcomatous) differentiation, carcinoma ex-pleomorphic adenoma of the breast, and invasive lobular carcinoma with extracellular mucin production [ 6 , 23 , 24 , 25 , 26 ]. An inspection of the histological detail paired with the appropriate immunohistochemical stains will usually resolve diagnostic dilemmas [ 22 ].…”

Update on lobular lesions of the breast

“…54,55 To date, 39 cases of ILCEM have been reported in the literature. 53,[56][57][58][59][60][61][62][63][64][65][66][67] These tumours were more frequently diagnosed in post-menopausal women (median age = 62 years; range = 31-87), primarily presenting with palpable masses. Multifocality was not uncommon, and most of the tumours (69%) were ≥ 2 cm (range = 0.7-10 cm).…”

Diagnostically Challenging Subtypes of Invasive Lobular Carcinomas: How to Avoid Potential Diagnostic Pitfalls

“…ILC with extracellular mucin production was first described by Rosa et al in 2009 [ 20 ]. A review of the relevant literature has yielded 12 papers describing 39 cases in toto [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ]. In some cases, important clinicopathological data, such as tumor size, lymph node, hormone receptor, Her−2 status, therapy, and follow-up information, are not mentioned.…”