Metastases to soft tissue: a review of 118 cases over a 30-year period.
BACKGROUND
Metastatic tumors presenting as soft tissue masses are relatively rare and can be the source of diagnostic confusion both clinically and pathologically. The authors' experience was reviewed at a large academic medical center over a 30-year period (1971-2000) with metastases to soft tissue.


METHODS
The tumors in the study included mainly lesions involving skeletal muscle or skeletal muscle and subcutaneous tissue of the upper and lower limbs, trunk, shoulders, and buttocks. Direct extension from tumors originating in bone or adjacent organs, tumors involving the skin or areas known to contain abundant lymph nodes (ie, axilla, groin), and hematopoietic malignancies were excluded.


RESULTS
One hundred and eighteen cases were identified; 60 patients were women and 58 were men. The age range was 20 to 87 years (median of 53.5 years). The primary tumor was located in the skin (19 patients), lung (13 patients), breast (13 patients), kidney (12 patients), colon and rectum (12 patients), uterus (8 patients), ovary (5 patients), head and neck (tongue, pharynx, larynx, nasal cavity, and mandible) (5 patients), esophagus (2 patients), stomach (2 patients), cervix (2 patients), small bowel (2 patients), bone (2 patients), adrenal gland (1 patient), eye (1 patient), testis (1 patient), urinary bladder (1 patient), and salivary gland (1 patient). In 27% (32 of 118 cases) of cases, the soft tissue metastasis was the initial manifestation of the disease. In 13.5% (16 of 118 cases) of cases the primary site of origin could not be identified. The sites of metastasis included the abdominal wall (25 patients), back, including scapular region (20 patients), thigh (17 patients), chest wall (15 patients), arm (15 patients), shoulder (11 patients), buttock (5 patients), perineum (3 patients), leg (2 patients), foot (1 patient), umbilical area (1 patient), ankle (1 patient), scalp (1 patient), and elbow (1 patient). The histologic classification of the tumors included carcinoma (83 patients), malignant melanoma (20 patients), sarcoma and carcinosarcoma (9 patients), malignant mixed Mullerian tumor (2 patients), seminoma (1 patient), malignant teratoma (1 patient), malignant gastrointestinal stromal tumor (1 patient), and neuroblastoma (1 patient). Many of the tumors displayed histologic features that created difficulties for diagnosis and could be easily mistaken on routine histopathologic examination for a variety of primary soft-tissue sarcomas. Routine use of immunohistochemical stains aided in their proper recognition.


CONCLUSIONS
Metastases are not an infrequent finding in soft tissue and they may represent the initial manifestation of the disease. Use of a basic panel of immunohistochemical stains is recommended for defining the cell type and arriving at the correct diagnosis.
Division of Anatomic Pathology, Department of Pathology, Ohio State University Medical Center and Arthur G. James Comprehensive Cancer Center, Columbus, Ohio, USA.
Jose Antonio
JA
Plaza
Delia
D
Perez-Montiel
Joel
J
Mayerson
Carl
C
Morrison
Saul
S
Suster
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008545:Melanoma / Q000473:pathology / Q000556:secondary; D008875:Middle Aged; D012509:Sarcoma / Q000473:pathology / Q000556:secondary; D012983:Soft Tissue Neoplasms / Q000378:metabolism / Q000473:pathology / Q000556:secondary*