Most patients present with a dominant breast mass tender to palpation [14][15]. This associated pain has been suggested to be due to the contractile myoepithelial component of these tumors, as perineural invasion is not commonly seen in these lesions [16] [17]. All quadrants seem to be affected, with a particular trend for the periareolar region [16].

1. Fine needle aspiration cytology (FNAC): It can be diagnosed on FNAC [18] [19]. The aspirates are cellular and show extracellular metachromatic material surrounded by uniform cells with scanty amount of cytoplasm. Cytology reveals atypical epithelial cells with absence of bare nuclei mimicking as atypical epithelial hyperplasia [20]( (Figure 1).
2. The core biopsy: It can be used as an effective diagnostic modality and reveal prominent solid, microcystic, and focally tubuloglandular patterns of growth with intact myoepithelial layer [20] (Figure 2).
3. Immunohistochemistry: On immunohisto-chemical evaluation, the tumor cells are immunopositive for CK7 expression (Figure 3) and myoepithelial cells are positive for p63 (Figure 4).
4. Histological grading: It is usually well circumscribed and with size ranging from 1–5 cm in [21]. According to previous workers, breast ACC can be graded on the basis of presence of solid areas in tumor microscopy and it was directly affecting the prognosis of the patients [22]. Proposed Grades were grade 1 (no evidence of solid areas); grade 2 (< 30% solid proportion); grade 3 (>30% solid areas) and the proposed treatment were local excision, simple mastectomy and mastectomy with axillary node dissection respectively.
5. Mammography: Although calcification may develop in these tumors detected rarely on mammography. In one series only, 4 of 22 patients detected radiologically [23].
6. Metastasis: Axillary lymph node metastases are rare in patients with ACC. Arpino et al. noted lymph node metastases in only 4 of the 182 cases collected from literature [4]. Distant metastases are uncommon with only 14 cases having been reported, but when they occur they tend to do so without prior lymph node involvement. Hence a routine axillary lymph node dissection is not recommended [4].
7. Estrogen receptor/progesterone receptor: ACC is generally estrogen receptor (ER) negative; in various series the ER was described as positive in 0.7–28% of the cases [23] [24]. Progesterone receptor (PR) was positive in three of the 13 evaluated patients [23]. Hence, hormonal manipulation is of limited use as most cases are ER.

Adenoid cystic carcinoma of the breast in females usually has very favorable biological characteristics for treatment [25] [26][27] [28]. It belongs to the basal-like subgroup of breast cancers [29]. Based on extensive molecular and genetic profiling studies, basal-like tumors are most often hormone receptor (ER and PR) negative and do not express human epidermal growth factor receptor 2 (HER2) [30] [31]. Adenoid cystic carcinoma has the excellent prognosis irrespective of IHC results [28]. The nodal and distant metastasis is lower as per existing literature [32]. It is because of these distinct clinic-pathologic features that set it apart from the other triple-negative breast cancers [33].

Surgical intervention is the basic treatment for ACC. The surgical treatment modalities include lumpectomy, wide excision, or MRM (modified radical mastectomy). The axillary clearance is not needed in majority of the patients. Lumpectomy with radiation or simple mastectomy has excellent results.

No clear guidelines are available for adjuvant chemotherapy or radiotherapy. According to previous studies (2011 St. Gallen International Expert Consensus), there is no need of adjuvant chemotherapy for ACC with absence of nodal metastasis. Radiotherapy is advised in patients with treatment plan aiming conservation of breast or in patients with large tumor size with nodal metastasis [33]. Hormonal therapy or anti-HER2 treatment is rarely indicated as ACC usually does not express hormonal receptors and HER2/neu.

Usually, the prognosis is excellent as compared to other breast malignancies and ACC of salivary glands [28] [34].

Adenoid cystic carcinoma of breast is a rare histological diagnosis. Early fine needle aspiration cytology/core biopsy and meticulous histopathological examination is mandatory in each and every palpable breast lump irrespective of age and clinical presentation to prevent untoward complications related to disease and treatment for the sake of accurate pathological diagnosis.

Keywords: Adenoid cystic carcinoma, Breast, Diagnosis and management

1. Alis H, Yigitbas H, Kapan S, Kalayci M, Kilic G, Aygun E. Multifocal adenoid cystic carcinoma of the breast: an unusual presentation. Can J Surg 2008 Apr;51(2):E36–7.   [Pubmed]    
2. Law YM, Quek ST, Tan PH, Wong SL. Adenoid cystic carcinoma of the breast. Singapore Med J 2009 Jan;50(1):e8–11.   [Pubmed]    
3. Billroth T. Die Cylindergeschwalst. Untersuchungen ueber die Entwicklung der Blutgefasse. Berlin: G. Reimer; 1856. P. 55–69.    
4. Arpino G, Clark GM, Mohsin S, Bardou VJ, Elledge RM. Adenoid cystic carcinoma of the breast: molecular markers, treatment, and clinical outcome. Cancer 2002 Apr 15;94(8):2119–27.   [CrossRef]   [Pubmed]    
5. Kshirsagar AY, Wader JV, Langade YB, Jadhav KP, Zaware SU, Shekhar N. Adenoid cystic carcinoma of the male breast. Int Surg 2006 Jul-Aug;91(4):234–6.   [Pubmed]    
6. Liu J, Jia W, Zeng Y, Deng H, Rao N, Su F. Adolescent male adenoid cystic breast carcinoma. Am Surg 2012 May;78(5):E288–9.   [Pubmed]    
7. Miliauskas JR, Leong AS. Adenoid cystic carcinoma in a juvenile male breast. Pathology 1991 Oct;23(4):298–301.   [CrossRef]   [Pubmed]    
8. Yoo SJ, Lee DS, Oh HS, et al. Male breast adenoid cystic carcinoma. Case Rep Oncol 2013 Oct 12;6(3):514–9.   [CrossRef]   [Pubmed]    
9. Woyke S, Domagala W, Olszewski W. Fine structure of mammary adenoid cystic carcinoma. Pol Med J 1970;9(5):1140–8.   [Pubmed]    
10. Verani RR, Van der Bel-Kahn J. Mammary adenoid cystic carcinoma with unusual features. Am J Clin Pathol 1973 May;59(5):653–8.   [CrossRef]   [Pubmed]    
11. Ferlito A, Di Bonito L. Adenoid cystic carcinoma of the male breast: report of a case. Am Surg 1974 Jan;40(1):72–6.   [Pubmed]    
12. Hjorth S, Magnusson PH, Blomquist P. Adenoid cystic carcinoma of the breast. Report of a case in a male and review of the literature. Acta Chir Scand 1977;143(3):155–8.   [Pubmed]    
13. Tang P, Yang S, Zhong X, et al. Breast adenoid cystic carcinoma in a 19-year-old man: a case report and review of the literature. World J Surg Oncol 2015 Feb 6;13:19.   [CrossRef]   [Pubmed]    
14. Anthony PP, James PD. Adenoid cystic carcinoma of the breast: prevalence, diagnostic criteria, and histogenesis. J Clin Pathol 1975 Aug;28(8):647–55.   [CrossRef]   [Pubmed]    
15. Lusted D. Structural and growth patterns of adenoid cystic carcinoma of breast. Am J Clin Pathol 1970 Sep;54(3):419–25.   [CrossRef]   [Pubmed]    
16. Rosen PP. Adenoid cystic carcinoma. In: Rosen PP ed. Rosen's breast pathology. 3ed. Philadelphia: Lippincott Williams and Wilkins 2009. p. 590–604.    
17. Bennett AK, Mills SE, Wick MR. Salivary-type neoplasms of the breast and lung. Semin Diagn Pathol 2003 Nov;20(4):279–304.   [CrossRef]   [Pubmed]    
18. Culubret M, Roig I. Fine-needle aspiration biopsy of adenoid cystic carcinoma of the breast: a case report. Diagn Cytopathol 1996 Dec;15(5):431–4.   [CrossRef]   [Pubmed]    
19. Stanley MW, Tani EM, Rutquist LE, Skoog L. Adenoid cystic carcinoma of the breast: diagnosis by fine-needle aspiration. Diagn Cytopathol 1993;9(2):184–7.   [CrossRef]   [Pubmed]    
20. Ingle SB, Jamadar NP, Adgaonkar BD, Hinge Ingle CR, Siddiqui S. An interesting pathological diagnosis - adenoid cystic carcinoma in an adolescent girl. Breast Cancer (Auckl) 2015 Jan 12;9:1–2.   [CrossRef]   [Pubmed]    
21. Cavanzo FJ, Taylor HB. Adenoid cystic carcinoma of the breast. An analysis of 21 cases. Cancer 1969 Oct;24(4):740–5.   [Pubmed]    
22. Ro JY, Silva EG, Gallager HS. Adenoid cystic carcinoma of the breast. Hum Pathol 1987 Dec;18(12):1276–81.   [CrossRef]   [Pubmed]    
23. McClenathan JH, de la Roza G. Adenoid cystic breast cancer. Am J Surg 2002 Jun;183(6):646–9.   [CrossRef]   [Pubmed]    
24. Leeming R, Jenkins M, Mendelsohn G. Adenoid cystic carcinoma of the breast. Arch Surg 1992 Feb;127(2):233–5.   [CrossRef]   [Pubmed]    
25. Pia-Foschini M, Reis-Filho JS, Eusebi V, Lakhani SR. Salivary gland-like tumours of the breast: surgical and molecular pathology. J Clin Pathol 2003 Jul;56(7):497–506.   [CrossRef]   [Pubmed]    
26. Perou CM, Sørlie T, Eisen MB, et al. Molecular portraits of human breast tumours. Nature 2000 Aug 17;406(6797):747–52.   [Pubmed]    
27. Di Palma S, Simpson RH, Marchió C, et al. Salivary duct carcinomas can be classified into luminal androgen receptor-positive, HER2 and basal-like phenotypes. Histopathology 2012 Oct;61(4):629–43.   [CrossRef]   [Pubmed]    
28. Boujelbene N, Khabir A, Boujelbene N, Jeanneret Sozzi W, Mirimanoff RO, Khanfir K. Clinical review--breast adenoid cystic carcinoma. Breast 2012 Apr;21(2):124–7.   [CrossRef]   [Pubmed]    
29. Sorlie T, Tibshirani R, Parker J, et al. Repeated observation of breast tumor subtypes in independent gene expression data sets. Proc Natl Acad Sci U S A 2003 Jul 8;100(14):8418–23.   [CrossRef]   [Pubmed]    
30. Miyai K, Schwartz MR, Divatia MK, et al. Adenoid cystic carcinoma of breast: Recent advances. World J Clin Cases 2014 Dec 16;2(12):732–41.   [CrossRef]   [Pubmed]    
31. Rakha EA, Elsheikh SE, Aleskandarany MA, et al. Triple-negative breast cancer: distinguishing between basal and nonbasal subtypes. Clin Cancer Res 2009 Apr 1;15(7):2302–10.   [CrossRef]   [Pubmed]    
32. Peters GN, Wolff M. Adenoid cystic carcinoma of the breast. Report of 11 new cases: review of the literature and discussion of biological behavior. Cancer 1983 Aug 15;52(4):680–6   [CrossRef]   [Pubmed]    
33. Ghabach B, Anderson WF, Curtis RE, Huycke MM, Lavigne JA, Dores GM. Adenoid cystic carcinoma of the breast in the United States (1977 to 2006): a population-based cohort Breast Cancer Res 2010;12(4):R54.   [CrossRef]   [Pubmed]    
34. Li N, Xu L, Zhao H, El-Naggar AK, Sturgis EM. A comparison of the demographics, clinical features, and survival of patients with adenoid cystic carcinoma of major and minor salivary glands versus less common sites within the Surveillance, Epidemiology, and End Results registry. Cancer 2012 Aug 15;118(16):3945–53.   [CrossRef]   [Pubmed]