ABSTRACT
Poorly differentiated spindle cell malignancies on sun damaged skin frequently pose a diagnostic challenge for dermatopathologists. The vast majority of these neoplasms ultimately are diagnosed as either atypical fibroxanthoma (AFX), spindle cell squamous cell carcinoma (SCSCC), or spindle cell melanoma (SCM), and rarely leiomyosarcoma or angiosarcoma. Light microscopic clues may suggest one of these neoplasms, but subtle and overlapping characteristics often render precise diagnosis impossible based on morphological features alone. Immunohistochemistry therefore is necessary to firmly and accurately diagnose the majority of spindle cell malignancies on sun damaged skin. We summarize typical clinical and histological findings associated with this group of malignancies and offer a practical immunohistochemical approach to use in their diagnosis.
Subject(s)
Histiocytoma, Benign Fibrous/diagnosis , Skin Diseases/diagnosis , Skin Neoplasms/diagnosis , Skin/radiation effects , Sunlight/adverse effects , Carcinoma, Squamous Cell/chemistry , Carcinoma, Squamous Cell/diagnosis , Carcinoma, Squamous Cell/pathology , Diagnosis, Differential , Histiocytoma, Benign Fibrous/metabolism , Histiocytoma, Benign Fibrous/pathology , Humans , Immunohistochemistry , Melanoma/chemistry , Melanoma/diagnosis , Melanoma/pathology , Skin/pathology , Skin Diseases/metabolism , Skin Diseases/pathology , Skin Neoplasms/chemistry , Skin Neoplasms/pathologyABSTRACT
In summary, cutaneous malignancies with an epithelioid appearance form a diverse group of neoplasms that may be difficult to diagnose by utilizing routine microscopy alone. Cutaneous malignancies, including malignant melanoma and metastatic carcinoma, certain benign neoplasms such as mixed tumor of the skin and angiolymphoid hyperplasia with eosinophils (epithelioid hemangioma), and infectious conditions such as bacillary (epithelioid) angiomatosis can be considered in this differential. However, through recognition of the characteristic histologic, immunocytochemical, and ultrastructural findings outlined above, definitive diagnosis of these challenging neoplasms is usually possible.
Subject(s)
Sarcoma/pathology , Skin Neoplasms/pathology , Diagnosis, Differential , Hemangiosarcoma/etiology , Hemangiosarcoma/pathology , Hemangiosarcoma/ultrastructure , Humans , Immunohistochemistry , Leiomyosarcoma/etiology , Leiomyosarcoma/pathology , Leiomyosarcoma/ultrastructure , Neurilemmoma/etiology , Neurilemmoma/pathology , Neurilemmoma/ultrastructure , Sarcoma/etiology , Sarcoma/ultrastructure , Skin Neoplasms/etiology , Skin Neoplasms/ultrastructureABSTRACT
BACKGROUND: Carcinoma ex pleomorphic adenoma is a rare neoplasm of the salivary gland. This lesion, also known as malignant mixed tumor, occurs when a malignant tumor arises in the epithelial component of a pleomorphic adenoma. Reports of fine needle aspiration biopsy (FNAB) diagnosis of malignant mixed tumors are rare and have been limited to cases arising in the parotid. Cytologic features and diagnostic pitfalls of this uncommon neoplasm are presented. CASE: A 75-year-old male presented with a nontender submandibular mass. The lesion had been present 12 months, with a recent increase in size. FNAB was performed, and the smears revealed a mixture of benign and malignant areas. The benign portion of the smears showed findings typical of pleomorphic adenoma. The malignant area showed large cells occurring singly and in groups. The malignant cells contained pleomorphic nuclei with irregular nuclear membranes and prominent macronucleoli; cytologically, they resembled cells from a poorly differentiated adenocarcinoma. CONCLUSION: We present the first case of carcinoma ex pleomorphic adenoma of the submandibular gland correctly diagnosed by FNAB. This rare salivary gland malignancy can be accurately diagnosed on FNAB if strict criteria are applied.
Subject(s)
Adenoma, Pleomorphic/pathology , Submandibular Gland Neoplasms/pathology , Aged , Biopsy, Needle , Humans , MaleABSTRACT
BP180 is a 180kDa hemidesmosomal protein recognized by bullous pemphigoid (BP) and pemphigoid gestationis (PG) autoantibodies. Recent cloning and sequence analysis performed by our laboratory have revealed that BP180 is a transmembrane protein with a long extracellular collagen-like region. A rabbit polyclonal antibody has been generated against a recombinant protein, designated GST-N delta 1, containing a segment of the BP180 ectodomain. The resulting antiserum, RN delta 1A, was shown to specifically react with BP180 on immunoblot, and labelled the extracellular region of the epidermal hemidesmosome on immunoelectron microscopy. A panel of normal and neoplastic human tissues were analysed by indirect immunofluorescence (IF) and RN delta 1A, to determine the distribution of BP180. A total of nine basal cell carcinomas (BCCs) and four squamous cell carcinomas (SCCs) of the skin were also studied. Intense IF staining was seen along the basement membrane zone (BMZ) of the epidermis, hair follicles, and the periphery of sebaceous gland lobules. The sebaceous lobules showed more intense staining in areas close to the duct. The epithelial BMZ of the following tissues also reacted with RN delta 1A: cornea, ocular conjunctiva, buccal mucosa, upper oesophagus, placenta (amnion placentum), umbilical cord and transitional epithelium of the bladder. The epithelium of the jejunum and ovary failed to react with RN delta 1A. Staining of the BCCs and SCCs was variable. Five of six nodular BCCs showed some anti-BP180 staining at the tumour-stromal interface, although the level of staining was less intense than that observed in the overlying normal epidermis. All three morphoeic BCCs analysed in this investigation did not show any staining with RN delta 1A. Three of four SCCs showed weak staining at the tumour-stromal interface. Thus, the tissue distribution of BP180 paralleled that of hemidesmosomes, and expression of this protein was found to be decreased or absent in cutaneous neoplasms.
