Needle Aspiration Cytology, Immunocytochemistry, and Electron Microscopy in a Rare Case of Secretory Carcinoma of the Breast in an Elderly Woman Raj K. Gupta, M.D., F.I.A.C., Sharda D. Lallu, B.Sc., Robert Fauck, C.T. (I.A.C.), John s. Simpson, M.B.Ch.B., F.R.C.S., F.R.A.C.S., and St John Wakefield, Ph.D.

Needle aspiration was performed on a breast mass in a 91-year-old woman. The cytologic features in the aspirate were a difluse, prominent, intracytoplasmic vacuolization and secretion in malig- nant cells and occasional signet ring-like forms. This was con- firmed in a subsequent cell block which was made from the aspi- rate. Immunocytochemical studies showed a positivity for mucin by alcian blue stain in the vacuolated cells which was periodic acid-Schiff positive and resistant to diastase digestion. Oil-red-0 staining was negative and on Colloidal iron stain the tumour cells wen? positive. Immunopositivity to carcinoembryonic antigen, cytokeratin, and epithelial membrane antigen was found in the malignant cells, while on electron microscopy the tumour cells contained a significant amount of intracytoplasmic secretory ma- terial. Secretory carcinoma of the breast is a rare tumour and can be diagnosed and differentiated from other breast carcinomas in view of its characteristic cytologic features. Diagn Cytopathol 199.2;8:388-391. 0 1992 Wiley-Liss, Inc.

Key Words: Malignant cells; Signet ring-like forms; Vacuolated cytoplasm

Secretory carcinoma of the breast, first described by McDivitt and Stewart,’ is an uncommon breast carci- noma. Although it was originally described in children and adolescent females, a few studies have shown that it rarely occurs in postmenopausal women. 3,4,6 Its cytologic features in needle aspirates have only been described re- ~ently.’-~ In this communication we describe a case of secretory carcinoma of the breast in an elderly female in

Received July 20, 1991. Accepted November 27, 1991. From the Department of Cytology and Surgery, Wellington Hospital

Address reprint requests to Raj K. Gupta, M.D., F.I.A.C., Cytology and School of Medicine, Wellington, New Zealand.

Unit, Wellington Hospital, Wellington, New Zealand.

which the diagnosis was made on needle aspiration cytol- ogy (NAC). The immunocytochemical and electron mi- croscopic findings in the aspirate are also presented for the first time with a pertinent differential diagnosis.

Case Report A 91-year-old female presented with a 3 x 2.5 cm firm mobile mass behind the nipple of the right breast of 3 months duration. In the last 2 weeks it had gradually increased in size. No family history of breast cancer was noted. Axillary lymph nodes were not enlarged. All bio- chemical and hematological investigations were normal. A bone scan was negative. On physical examination all systems were normal. The mass was aspirated using a 22 gauge needle and reported as malignant. In view of her failing health she was not considered suitable for surgery and was treated with tamoxifen. She is alive and well six months following the NAC diagnosis.

Cytohistochemical Findings Papanicolaou-stained Schleicher and Schuell filter prepa- rations, Cytospin preparations, and hematoxylin and eosin stained preparations of the cell block from the as- pirated material showed a high cellularity containing nu- merous malignant epithelial cells both singly and in small clusters. The tumour cells were somewhat polygonal with abundant vacuolated cytoplasm and rare signet ring-like forms. The nuclei were enlarged, vesicular, round to ovoid, with moderately coarse chromatin and small prom- inent nucleoli (Fig. 1). Mitoses were rare. The histologic features of the tumour with the above-mentioned secre- tory features were further confirmed in cell block prepara-

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CYTOLOGY OF SECRETORY CARCINOMA OF THE BREAST

Fig. 1. Filter preparation of aspirate showing tumour cells with vacuola- ted-granular cytoplasm (Papanicolaou stain; X 500).

Fig. 2. Cell block preparation showing histologic features of the secre- tory carcinoma. (A) Low power view. (B) High power view, with a majority of cells having vacuolated cytoplasm (hematoxylin eosin stain; A, ~ 2 0 0 , B, x500.)

tions which were subsequently made from the aspirate (Fig. 2A,B).

On Colloidal iron, alcian blue, and periodic acid-Schiff (PAS) stain, with and without prior diastase digestion, the

tumour cells showed a diffuse positivity of the cytoplasm and intravacuolar material. Only a few cells showed a minimal positivity on mucicarmine stain while an air dried smear on oil-red-0 stain was found to be negative.

Im m u n operoxidase Fin dings For immunoperoxidase studies, Cytospin and smear prep- arations were made from aspirated material. Sections from the cell block were also utilised. Immunostaining for carcinoembryonic antigen (CEA), cytokeratin, epithelial membrane antigen (EMA), and B72.3 was performed uti- lising commercially available kits for immunoperoxidase methods (A 115 for CEA, CAM 5.2 for cytokeratin, RPN 1130 for EMA, all supplied by Dako; and B72.3, supplied by Bio Med). The immunostaining for CEA, EMA, B72.3 and cytokeratin showed a strong positivity in the malig- nant epithelial cells (Fig. 3A,B). Known positive and neg- ative controls were used during all the procedures.

Electron Microscopic Findings For electron microscopy a cell button from the aspirate material was made after centrifuging and cut into 1 mm cubes, fixed in half strength Karnovsky’s fixative, embed- ded in Epon and examined with a Siemans 102 electron microscope. On ultrastructural study the epithelial tu- mour cells contained a significant number of membrane bound secretory vacuoles and inspissated secretory mate- rial. Intercellular lumina with projecting microvilli were seen (Fig. 4).

Discussion Secretory carcinoma is an unusual breast tumour in which the diagnosis by NAC has only been described recently. 7-9

The prognosis of secretory carcinoma is generally better than that of ductal carcinoma of the breast. The NAC features of secretory carcinoma are quite characteristic with the presence of diffuse intracytoplasmic secretions in more than 75% of tumour cells, the remainder being ad- mixtures of ductal-lobular type. This was also seen in the case described herein. Therefore, we feel that its correct cytologic distinction is possible, in NAC samples, from infiltrating ductal carcinoma, in which the secretory sub- stance and vacuolated cells are rare. Also, the cells in infiltrating ductal carcinoma are predominantly seen as small and large clusters with a three-dimensional arrange- ment while in secretory carcinoma the tumour cells are mostly single with occasional small clusters and abundant vacuolated cytoplasm.

The other tumour which may result in a difficulty of diagnosis is the infiltrating lobular carcinoma, in which signet ring type cells may be present. Again, in this tu- mour, granular or vacuolated cells are not seen diffusely as in a secretory carcinoma. Apart from this, the tumour

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GUPTA ET AL.

Fig. 3. Cytospin preparations from aspirate showing immunopositivity for (A) CEA and (B) B72.3 (X400).

cells are usually seen as dissociate to loose aggregates of monomorphic cells, generally showing an Indian-file ar- rangement.

In a study, lo it was suggested that these tumours were all variants of a well-established breast carcinoma with no difierence in survival and treatment. In view of the rarity of secretory carcinoma it is not surprising that the admix- ture of ductal-lobular components may result in interpret- ing them as an infiltrating ductal-lobular carcinoma in NAC material. This has been suggested by Kline and Kline" with whom we are in agreement. Despite our limited experience, we feel that this tumour can be diag- nosed by NAC due to the typical findings, and the admix- ture of a ductal-lobular pattern should not be a reason to misinterpret these.

A recent study' has also suggested that the specific cytologic diagnosis of secretory carcinoma from other types of breast cancers, such as lipid rich carcinomas, can be difficult. We, like others, ',',' feel that the use of special stains, such as oil-red-0, in air dried smears is quite useful

Fig. 4. Part of a tumour cell with a large vacuole full of secretory material; much of the rest of the cytoplasm contains secretory vesicles ( X S S O O ) .

in making the distinction. Also the finding of PAS-D posi- tive intracytoplasmic material in the tumour cells is quite useful in suggesting the diagnosis of secretory carcinoma in aspirated material. Other stains like Colloidal iron, im- munopositivity of various markers, and electron micro- scopic study on aspirated material, as we have used for the first time, may also be quite useful in lending further support to the diagnosis.

In summarising, we feel that the diagnosis of the rare secretory carcinoma of breast from aspirate material is possible. This is quite important since a diagnosis by NAC can permit a preoperative assessment and appropriate de- cision for management.

Acknowledgments The authors gratefully acknowledge the fine technical assistance of Andrew McHutchison and Caroline Hope.

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CYTOLOGY OF SECRETORY CARCINOMA OF THE BREAST

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