Crystallizing galactocele: Report of a rare variation

Abstract

The physiological changes of the breast during pregnancy and lactation make the clinical, radiological and pathological evaluation of a breast mass challenging. Galactoceles are benign lesions containing milk, and generally occur post partum. Fine needle aspiration cytology is a simple, quick and effective technique for the diagnosis of the same during this period, and in case of galactocele the same can be both diagnostic and therapeutic.

Although the cytological features of galactocele are straight forward, a few rare interesting variations can be encountered posing a diagnostic challenge to the reporting cytopathologist. We present a case of galactocele in a twenty five year old lactating female with tyrosine crystals on cytology. Milk is composed of a wide variety of proteins and minerals, leading to the formation of calcium lactate or tyrosine crystals under rare circumstances when the milieu is acidic. This is one of the rare cases of crystallizing galactoceles reported in literature till date.

Introduction

A variety of lesions are encountered in women during pregnancy and post-partum. A galactocele is an uncommon benign lesion of the breast occurring in pregnant and lactating women [1]. Fine needle aspiration cytology [FNAC] is a simple and minimally invasive diagnostic procedure in cases of galactocele. Although the cytological features on aspirates are straight forward, very few cases with extensive crystallization have been documented till date. We report a case of crystallizing galactocele, the crystals in our case being those of tyrosine as seen on cytology smears.

Case report

A 25 year old female, presented with complaint of a slowly growing painless lump in the right breast noticed by her since two months. The lady had delivered her first child and was lactating since nine months. She had conceived naturally, with no history of any previous medications, including oral contraceptives. On examination, a mobile, non-tender, nodular lump, measuring 3 × 2  cm was palpable in the upper outer quadrant of the right breast. Nipple and areola were unremarkable. Blood investigations showed serum prolactin levels to be 58 ng/ml, and haemoglobin was 10.9 g/dl. FNAC was done under aseptic precautions using a 21 gauge needle and a 5 ml syringe, after explaining the procedure and taking the patient’s consent. Chalky milky white material was aspirated on two passes. The lump reduced in size after aspiration. Smears were stained with routine Haematoxylin and Eosin (Fig. 1), Pap (Fig. 2) and Giemsa stains. Microscopy showed plenty of amorphous pink eosinophilic material, with lipid micelles. Cyst and foamy macrophages, many showing degenerative changes were noted. Background showed proteinaceous material. Occasional scattered benign ductal epithelial cells were noted. Also seen were sheaves of needle like structures of varying sizes with well defined borders on haematoxylin and eosin stain. A closer look at the same showed them to be highly refractile, thin crystals with sharp borders. The crystals also showed birefringence under the polarizing microscope (Fig. 3a and 3b). In view of the supportive clinical history a diagnosis of crystallizing galactocele was conferred.

Discussion

Palpable nodular lesions in the breast of pregnant or lactating women require prompt attention. Although most of the palpable breast lesions in them are benign, about 3% of them are diagnosed as breast cancers [1]. Galactoceles are benign lumps occurring commonly in post the partum period. Nevertheless, a few cases have been described in male and female infants [7]. Galactocele associated with chronic galactorrhea caused by a pituitary adenoma has been reported [7]. In our case the lady was in her postpartum period, breast feeding the baby since nine months and had appropriate serum prolactin levels.

A galactocele is defined as an encysted collection of milk products and is lined by flattened cuboidal epithelium. Ductal obstruction, secretory type of breast epithelium and prolactin stimulation as in pituitary adenoma are a few postulated factors contributing to its development [1,5].

On ultrasonography, these lesions are typically well circumscribed, ovoid, anechoic or hypoehoeic masses with posterior enhancement or fat fluid level, a feature useful in differentiating it from solid breast tumours [6]. In our case ultrasonography was not asked for.

FNAC is not only a simple, and minimally invasive procedure, but also its major advantage in pregnant women is avoidance of surgical trauma and anesthesia. It is also inexpensive and time saving. Surgery in these patients may also result in poor healing [5]. On FNAC galactoceles yield chalky white milky fluid, as in our case which by itself is diagnostic [4].

Microscopy shows necrotic cells and nuclear debris, sometimes accompanied by inflammatory cells. In some cases the fragile cytoplasm of the cells disintegrates and only nuclei stripped of cytoplasm (naked nuclei) are seen. These large nuclei may mislead an uninformed observer into believing that cancer is present, leading to tragic consequences. Smears also at times show scattered foamy macrophages. However ductal epithelial cells are rarely seen [5,7].

A rare variation in the aspirate of galactocele is presence of crystals on smear, first case of which was documented in 1997 by Raso et al. [2]. These crystals demonstrated polarization and birefringence and were found to be positive with Von Kossa stain, Alizarin red and Periodic acid Schiff stain. They were found to be composed of calcium, potassium, chlorine and sulphur. Only two more cases of finding such crystals in galactocele have been reported till date. However, none of the cases have categorized the morphology of the crystals [3,7].

The smears in our case showed crystals looking similar to tyrosine crystals seen in urine cytology. Also the birefringence was seen under polarizing microscope, as for tyrosine crystals. Milk is an emulsion or colloid of butterfat globules within a water-based fluid that contains dissolved carbohydrates and protein aggregates with minerals. Long standing milky fluid, acts as a nidus for crystal formation The two important factors contributing to formation of crystals is an acidic environment and supersaturation of the substances, thereby exceeding their solubility. For the crystals to form there must be sufficient contact between the reactants, namely calcium and lactate or calcium and tyrosine [8]. The long standing galactocele in our case may have been a good soil for the formation of tyrosine crystals. Only two more cases of finding such crystals in galactocele have been reported till date. In both the cases however composition of the crystals was not documented [3,7].

Conclusion

Galactoceles on cytology can show inspissated secretions in the form of crystals, often in long standing cases. The reporting cytopathologist must be aware of this unusual finding which is quite rare while reporting galactoceles on needle aspirates. This awareness being all the more important during the absence of other classical features of a galactocele on aspirate smears.