Fine needle aspiration cytology of cutaneous and subcutaneous metastatic deposits from epithelial malignancies. An analysis of 146 cases.

OBJECTIVE

To analyze cases suggestive of cutaneous/subcutaneous metastatic deposits from a known carcinoma or as the first manifestation of an unknown carcinoma using fine needle aspiration cytology (FNAC).

STUDY DESIGN

The study group consisted of 146 patients (86 males and 60 females) ranging in age from 34 to 82 years. In 135 cases there was a previous history of carcinoma, and in these cases FNAC showed the tumor to be similar to the carcinoma that had been treated by surgery and/or radiotherapy. In 11 patients no tumor had been found previously, and the site of the unknown primary was suggested by immunostaining. Aspirations were performed using a 22-gauge needle. The material was collected in 30% ethyl alcohol, and filter preparations and cell blocks were made.

RESULTS

The size of metastatic nodules ranged from 1.5 to 2 cm. The sites of metastases were on the chest wall (n = 35), back (n = 8), abdomen (including umbilicus) (n = 46), head and neck (n = 35), upper extremity (n = 12), lower extremity ((n = 6), penile skin (n = 1) and vulva (n = 3). The sites of known primary carcinomas were breast (n = 39), lung (n = 35), gastrointestinal tract (n = 38), endometrium (n = 2), cervix (n = 3), urinary tract (n = 4), prostate (n = 3), hand (n = 1), scalp (n = 1), tongue (n = 1), brain (n = 1), ear (n = 3) and ovary (n = 4). The sites of primary carcinomas unknown at the time of aspiration and found after FNAC were the gastrointestinal tract (n = 3), lung (n = 2), prostate (n = 1), breast (n = 3), liver (n = 1) and kidney (n = 1). No false negatives or positives were observed, and no second primary tumors were found. Cytologic preparations were sufficient for diagnosis and typing in tumors with a known primary tumor. Immunostaining was helpful in establishing a diagnosis of carcinoma and in determining the likely primary site in tumors with unknown primaries.

CONCLUSION

Cutaneous and subcutaneous metastatic deposits from previously known carcinomas can be diagnosed rapidly and accurately utilizing FNAC. A combination of FNAC and immunostaining may also help define the site of an unknown primary.