Fine needle aspiration cytology of invasive micropapillary carcinoma of the breast: review of cases in a three-year period

Comprehensive Review of Metastatic Breast Carcinoma in Cytology Specimens

Breast carcinomas are known to metastasize to various organs of the human body. Fine needle aspiration cytology or exfoliative cytology often are the standard method for diagnosis at these metastatic sites due to ease of procurement of diagnostic material, accessibility, less complications, high sensitivity, and specificity of diagnosis and evaluation of biomarker status needed to guide future management. This comprehensive review article discusses in detail metastatic patterns, cytomorphology of metastatic breast cancer at different body sites, immunohistochemistry needed for diagnosis of breast carcinoma, sensitivity and specificity of diagnosis and breast biomarker assays in the cytology material.

Cytologic diagnosis of pulmonary adenocarcinoma with micropapillary pattern: does it correlate with the histologic findings?

Micropapillary adenocarcinoma is associated with poor-prognosis in several organs including the lung. The presence of small tight balls of neoplastic cells devoid of fibrovascular core in cytological preparations (micropapillary tufts) has been described as characteristic of micropapillary adenocarcinoma. In the lung, however, this criterion has not been validated. The cytological material of 46 cases of histologically proven pulmonary adenocarcinoma with a micropapillary component was compared to 33 cases with no micropapillary component to determine the specificity of micropapillary tufts for the histologic diagnosis of micropapillary adenocarcinoma. Other histologic patterns of invasive pulmonary adenocarcinomas (acinar, papillary, and solid) were also compared with patterns of neoplastic cell aggregates in cytological preparations. There were no significant differences in the distribution of micropapillary clusters between the two groups. The positive predictive value for the cytologic diagnosis of a micropapillary component in lung adenocarcinomas was of 64%. Similar findings were observed for other invasive patterns. Therefore, the detection of micropapillary tufts in cytology is not specific for the diagnosis of a pulmonary micropapillary adenocarcinoma in the lung.

Fine needle aspiration cytology of invasive micropapillary carcinoma of the breast

AIM

To determine the pathognomonic diagnostic cytological features of invasive micropapillary carcinoma of the breast which is a poor prognostic subtype of infiltrating ductal carcinoma.

METHODS

A series of 20 histologically proven tumours were reviewed retrospectively to evaluate the various cytological features, including tumour morules, isolated malignant cells, staghorn epithelial structures, mucinous background and apocrine metaplasia.

RESULTS

Tumour morules formation and isolated malignant cells were the two most reliable and constant cytological features, being present in 75% (15/20 cases) of cases. Staghorn epithelial structures were present in 35% (7 cases). Mucinous background (2 cases, 10%) and apocrine metaplasia (4 cases, 20%) of the tumour cells were seen in a few cases only and did not appear very helpful.

CONCLUSION

Tumour morules formation, isolated malignant cells and staghorn epithelial structures are the most reliable cytological features, and the presence of these should raise suspicion of invasive micropapillary carcinoma.

Fine-needle aspiration cytology of medullary breast carcinoma: report of two cases and review of the literature with emphasis on differential diagnosis

Medullary carcinoma is a rare variant of breast carcinoma with a relatively good clinical prognosis as strictly defined. Characteristic features on fine-needle aspiration cytology (FNAC) allow medullary carcinoma to be considered in the cytologic differential diagnosis. We present two FNAC cases with such features, including high cellularity with clusters and single intact malignant cells, bizarre stripped nuclei with prominent nucleoli in a lymphoplasmacytic background, and illustrate one case in liquid-based preparation. Surgical excision revealed that one patient had medullary carcinoma, while the second patient had high-grade infiltrating ductal carcinoma. Breast FNAC samples with syncytial fragments, bizarre nuclei with prominent nucleoli, and a chronic inflammatory infiltrate should raise the possibility of medullary carcinoma. However, the differential diagnosis also includes high-grade ductal carcinoma, lymphoma, or metastasis to breast or intramammary lymph nodes; thus, histopathologic analysis is required for definitive diagnosis.

Micropapillary clusters in early-stage lung adenocarcinomas

BACKGROUND

It is known that patients who have pulmonary adenocarcinomas with a pathologic micropapillary pattern (pMPP) featuring small papillary tufts that lack a central fibrovascular core have a poor prognosis. Although the pMPP initially was identified in surgical material, preoperative detection is desirable from the standpoint of making treatment decisions. Therefore, the authors focused on cytologic features resembling the pMPP in lung adenocarcinomas, with particular reference to the survival of patients with pathologic Stage I disease.

METHODS

The authors reviewed clinical course data, preoperative cytologic specimens, and histologic materials from 110 patients with Stage I adenocarcinoma of the lung who presented between 1986 and 1995. Cytology of micropapillary clusters (MPCs) was characterized by round, 3-dimensional, cohesive clusters of neoplastic cells (consisting of > 3 cells and < 20 cells) with a pseudopapillary configuration. Total counts of cohesive clusters that consisted of more than three neoplastic cells on slides and frequencies of MPCs were investigated.

RESULTS

All patients (54 females and 56 males) had a preoperative diagnosis of malignancy and underwent complete surgical resection. The patients with Stage I disease were subclassified into an MPC-positive group (n = 41) and an MPC-negative group (n = 69). The 5-year survival rate was 91.3% for patients in the MPC-negative group and 75.6% for patients in the MPC-positive group; this difference was statistically significant.

CONCLUSIONS

MPC cytology is a distinct prognostic marker for early-stage lung adenocarcinoma with poor prognosis. The presence of this component, therefore, should alert the clinician to the need for close follow-up.

Fine-needle aspiration cytology findings of an uncommon micropapillary variant of pure mucinous carcinoma of the breast: review of patients over an 8-year period

BACKGROUND

Previous attempts at subclassifying pure mucinous carcinomas of the breast based on architectural patterns and other associated features are on record. A distinctive micropapillary variant with most tumor cells arranged in micropapillae/pseudoacini has not been described previously.

METHODS

The author reviewed the histologic slides from all 556 patients who underwent wide excision/mastectomy for mammary ductal carcinoma, either in situ or invasive, at Pamela Youde Nethersole Eastern Hospital, Hong Kong, during an 8-year period from early 1994 to the end of 2001. Five patients with pure mucinous carcinoma with diffuse micropapillary architecture were noted. The cytologic features (if available) were correlated with clinical, radiologic, and pathologic findings.

RESULTS

Among the five patients with pure mammary mucinous carcinoma (micropapillary variant), three patients underwent preoperative fine-needle aspiration biopsies and had specimens available for review. The direct smears and cytospin preparations were of moderate cellularity and showed cohesive clusters and micropapillae of mildly pleomorphic tumor cells among a mucoid background. True tumor papillae with fibrovascular cores were not present. Nuclear hobnailing was observed commonly, and occasional psammoma bodies were found. There were also scanty isolated tumor cells scattered around. The pseudoacinar pattern was appreciated more readily in the cell block sections. Histologic examination of the surgical specimens showed features of pure mucinous carcinoma with diffuse micropapillary architecture. The micropapillary arrangement was confirmed further by the demonstration of a reverse polarity immunostaining pattern for epithelial membrane antigen and the identification of microvilli rimming the periphery of tumor cell clusters under the electron microscope. Peritumoral lymphovascular permeation and ipsilateral axillary lymph node metastasis was found in one of the patients.

CONCLUSIONS

The micropapillary variant of mammary mucinous carcinoma demonstrates characteristic cytologic and histologic features that warrant special attention. It may represent the mucinous counterpart of invasive micropapillary carcinoma. Further analysis of a larger series of patients, however, will be required to delineate its prognostic significance, especially its propensity for lymph node metastasis.

Fine-needle aspiration biopsy of invasive micropapillary carcinoma of the breast: a report of five cases

Invasive micropapillary carcinoma of the breast is an uncommon variant of infiltrating ductal carcinoma. Observing its distinctive cytologic appearance and aggressive behavior is important for early diagnosis by fine-needle aspiration cytology (FNAC). There are only a few reported cases in the literature. Five women presented with breast masses. FNAC showed malignant epithelial tumors, and mastectomy materials showed invasive micropapillary carcinoma for all of them. Three patients had axillary lymph node metastases. Invasive micropapillary carcinoma, with its angulated papillary clusters lacking a fibrovascular core, and irregular crowded nuclei, has a distinctive cytologic appearance which correlates with its histological features. A differential diagnosis from other primary or metastatic papillary lesions of the breast may be possible using immunohistochemistry and some cytologic features. The limited experience with invasive micropapillary carcinoma should not discourage others from undertaking further studies.