Differential Diagnosis of Actinic Keratosis vs Lentigo Maligna

A 77-yr-old man was evaluated by his dermatologist and found to have a macular, irregular hyperpigmented patch on his face. He had extensive sun damage and a history of many previous actinic keratoses and basal cell carcinomas. The clinical differential diagnosis included pigmented actinic keratosis, solar lentigo and lentigo maligna type of melanoma in situ. Biopsies were performed and are depicted in Fig. 7. Differential Diagnosis of Actinic Keratosis and Lentigo Maligna Differential...

Cd99

S. (1985) Leukocyte common antigen a diagnostic discriminant between hematopoietic and nonhematopoietic neoplasms in paraffin sections using monoclonal antibodies correlation with immunologic studies and ultrastructural localization. Hum. Pathol. 16, 353-365. 2. Fischer, E. H., Charbonneau, H., Cool, D. E., and Tonks, N. K. (1992) Tyrosine phosphatases and their possible interplay with tyrosine kinases. Ciba Found. Symp. 164, 132-140. 3. Clark, E. A. and Ledbetter,...

Differential Diagnosis of Densely Cellular Spindle Cell Tumor

A 70-yr-old man presented with a slightly hyperpigmented nodule on his hand that had been growing slowly for the past 3-4 mo. It was not painful and he was otherwise in good health. The nodule was firm and had no overlying surface changes. The clinical differential diagnosis included dermatofibroma, dermatofibrosarcoma protuberans, Kaposi's sarcoma and a foreign body giant cell granulomatous reaction. A biopsy was performed and is represented in Fig. 5A,B. The histologic differential diagnosis...

Differential Diagnosis of Dermatofibroma vs Dermatofibrosarcoma Protuberans

A 42-yr-old woman presented to the dermatologist with a multinodular 1.3 cm hyperpigmented growth on her shoulder. She claimed Fig. 11. (A) A tumor comprised of small dark cells coursing throughout the dermis in large nests is present. There is no cleft artifact present surrounding the epithelial islands. (B) There are spaces within the epithelial islands. No definitive ductular differentiation is seen. Fig. 11. (A) A tumor comprised of small dark cells coursing throughout the dermis in large...

Lymphocyte Markers Kappa and Lambda Light Chains

In the circulating blood, approx 70 of B lymphocytes produce kappa light chains and the other 30 lambda light chains. This ratio is similar to that seen in lymphocytes present within the dermis. This biologic property can be used to assess for the presence of clonality in B cell infiltrates within the skin. Antibodies directed against kappa and lambda light chains could be difficult to interpret. The antibodies are nonspecifically adsorbed by dermal collagen, giving a very high background blush...

CD79a

CD79 has two components known as CD79a and CD79b. The antigen is expressed by B lymphocytes prior to the expression of immunoglobulins. It is present in B cells throughout maturation, but disappears as they evolve into plasma cells (18). Fig. 4. B cells in reactive germinal centers express CD20. A surrounding collarette of CD20 negative T cells is also seen. Fig. 4. B cells in reactive germinal centers express CD20. A surrounding collarette of CD20 negative T cells is also seen. Fig. 5. CD79a...

Cd10

CD10 also known as cALLA is a marker for immature B lymphocytes. It was initially identified as a very early marker expressed by lymphoblastic leukemia cells (8). It is one of many exopeptidases that is involved in activation and deactivation of peptides. CD10 functions as a useful marker for B-lineage lymphomas. However, it is less specific than was originally thought and can be seen on a wider range of leukemias and lymphomas (8). CD10 is also expressed by some follicular center cell...

Info

Ossifying fibromyxoid tumor of soft parts Malignant peripheral nerve sheath tumor Mixed tumors of the skin Breast carcinoma Salivary gland tumors Lung carcinomas *Paraffin-embedded, formalin-fixed tissue, pretreatment with trypsin necessary for monoclonal antibodies with some manufacturers, no pretreatment necessary for polyclonal antibody, cytoplasmic and nuclear staining. tic melanomas express this protein, and virtually none of the other neoplasms in this histologic differential diagnosis do...

Differential Diagnosis of Basal Cell Carcinoma vs Appendageal Neoplasm

A 37-yr-old man presented with a 1 cm nodule on his posterior neck. The tumor had no epidermal changes, was not tender, and was firm and freely mobile. There was an extended clinical differential diagnosis. The histologic sections are represented in Fig. 11A,B. Abundant ductular or pseudoductules are present admixed with islands of basaloid cells. The characteristic cleft artifact often present in basal cell carcinomas is not present. The differential diagnosis included a basal cell carcinoma...

Summary

Anti-factor XIIIa antibodies play a limited role in diagnostic der-matopathology. The antibody is particularly useful in the distinction Fig. 10. Many cells express factor XIIIa in dermatofibromas. Fig. 10. Many cells express factor XIIIa in dermatofibromas. Fig. 11. The large, atypical and stellate cells in pleomorphic fibromas express factor XIIIa. Fig. 11. The large, atypical and stellate cells in pleomorphic fibromas express factor XIIIa. between dermatofibroma and dermatofibrosarcoma...

I

Immunopathology is a scientific discipline that enables diagnostic pathologists to visualize cellular characteristics not apparent by routine histochemical stains. Immunopathologic techniques have evolved over the past twenty years and continue to evolve at a rapid pace. The scientific methods behind the process have remained largely stable, but techniques designed to enhance sensitivity and specificity are being discovered continuously. In addition, the immu-nologic probes available to...

CD34 Introduction

CD34, also known as the human progenitor cell antigen (HPCA-1), is a glycolated, 110 kD transmembrane glycoprotein. It is expressed on hematopoietic precursor cells in both the lymphoid and myeloid lines, as well as on the abluminal surfaces of vascular endothelium (41). It is expressed by osteoclast precursors and by a population of cells known as dermal dendrocytes (42). These cells have the ability to express either CD34 or factor XIIIa. They are involved in the cutaneous immune response and...

Differential Diagnosis of Blue Cell Tumors

A 27-yr-old woman presented to her local dermatologist with a 1 cm tender nodule on her forearm. She claimed it had been there for about 2 mo and was very tender to palpation. Examination revealed a dermal nodule with no overlying epidermal changes. The clinical differential diagnosis included angiolipoma, eccrine spiradenoma, glomus tumor and leiomyoma. A biopsy was performed. The histologic changes are depicted in Fig. 3A,B. The differential diagnosis included glomus tumor, eccrine...

CD31 Introduction

The CD31 antigen, also known as PECAM-1 (platelet endothe-lial cell adhesion molecule) corresponds to the platelet glycopro- tein gpIIa and is found on endothelial cells (59). CD31 appears to play a vital role in the development of endothelial cell tube formation and the creation of dermal blood vessels during angiogenesis. It is a member of the immunoglobulin superfamily and interacts with filamentous actin (60). The antigen is a 130-140 kD protein that functions, at least in part, as an...

Rmg

Technical considerations for immuno- staining, 57, 58 tumor expression, 55, 56 Actinic keratosis, differential diagnosis vs lentigo maligna, 172, 174 AEC, see Aminoethylcarbazol Alkaline phosphatase, colorimetric detection system, 17 Aminoethylcarbazol (AEC), colorimetric detection, 16, 17 Androgen receptor, diagnostic utility, 45-47 technical considerations for immuno- staining, 46 tissue distribution, 45 Antibody, monoclonal vs polyclonal, 18 primary, 17, 18 secondary, 19 Antigen retrieval,...

Vignette K Differential Diagnosis of Mycosis Fungoides

A 72-yr-old man presented to the dermatology clinic with a known 5-yr history of erythematous patches on his proximal trunk and extremities. The patches initially responded to topical steroids, but more recently persisted even with treatment. The differential diagnosis included contact dermatitis, mycosis fungoides, and a drug eruption. Several punch biopsies were performed and are demonstrated in Fig. 21A,B. The histologic differential diagnosis included a partially treated spongiotic...

Diagnostic Utility

Antibodies directed against CD34 are useful in the work-up of putative vascular neoplasms Fig. 6, Table 3 . The antibody has been shown to be more sensitive than is CD31 in identifying the proliferating cells in Kaposi's sarcoma 45 . Some authors have reported decreased sensitivity with this antibody in detecting neoplastic endothelial cells in angiosarcomas, spindle cell hemangioendotheliomas and some cases of bacillary angiomatosis 46 . This is especially true within poorly differentiated,...

Cd43

CD43 is a pan-T lymphocyte surface marker, less commonly known as leukosialin or sialophorin 46 . It is an integral cell membrane mucin and appears on hematopoietic cells during embryogenesis 47 . It is expressed in adults in all bone marrow derived cells except in resting B lymphocytes. Thus, tissue macrophages, dendritic cells and cells in myeloid and some lymphoid leukemias express CD43 Fig. 15 . Some endothelial cells, epithelial cells, and smooth muscle cells also can express CD43 48 . It...

Differential Diagnosis of Cutaneous Lymphoid Infiltrate

A 61-yr-old woman presented to her dermatologist with an erythematous 2 cm nodule on her forehead. There were no epidermal changes and the nodule was firm to palpation. The clinical differential diagnosis included cutaneous lymphoma, lymphocytoma cutis reactive lymphoid hyperplasia , granuloma annulare and Jessner's lymphocytic infiltrate. A biopsy was performed and revealed the histologic changes seen in Fig. 9A,B. The histologic differential diagnosis included lymphoma cutis probable B cell...

Immuniopathology In Ductal Casinoma Metastasis

As is the case with the other antibodies discussed in this chapter, there is little need for this antibody on a routine, daily basis in diagnostic dermatopathology. It may be helpful in distinguishing Merkel cell carcinomas from metastatic small cell carcinomas, and in defining a metastatic tumor as being from the thyroid gland, but these situations are unlikely to arise on a regular basis in most laboratories. Antibodies directed against alpha-fetoprotein, human chorionic gonadotropism and...

Cd68

There are many antibodies directed against the macrophage-associated antigen CD68. CD68 is a 110 kD cytoplasmic glycopro-tein and antibodies directed against several of its epitopes are available 61 . CD68 is a sialic acid binding lectin with relationship to the immunoglobulin superfamily 62 . The staining patterns of anti-CD68 antibodies differ slightly, but largely overlap. Several of these antibodies survive formalin-fixation and paraffin-embedding 61 . The same antigen is also present in...

Differential Diagnosis of Spongiotic Dermatitis in a Child

A 5-wk-old boy was seen in the dermatology clinic with a diffuse erythematous, scaly eruption that was most extensive on his face, neck and scalp. It was not noticed at birth, but appeared within the first week of life and continued to progress. The clinical differential diagnosis included atopic dermatitis, seborrheic dermatitis, and Langerhans cell histiocytosis. The histologic sections prepared from the biopsy specimen are demonstrated in Fig. 15A,B. The histologic differential diagnosis of...

Ii

The development of anti-cytokeratin antibodies as diagnostic tools is a long and constantly evolving story. Cytokeratins are one type of intermediate filament that is expressed by epithelial cells. There are currently more than 30 subtypes of cytokeratin. Keratins are divided into two subfamilies based upon isoelectric points 1 . Those with pIs less than 5.5 are termed the acidic subfamily and those with pIs greater than 6 are the basic subfamily. Keratinocytes characteristically express pairs...

Differential Diagnosis of an Atypical Dermal Spindle Cell Proliferation

The patient is an 82-yr-old man who presented with an ulcerated nodule on his right ear that had been present for about 6 mo. The clinical differential diagnosis included squamous cell carcinoma, basal cell carcinoma, amelanotic melanoma, and atypical fibro-xanthoma. A small shave biopsy was performed yielding the following tissue sections Fig. 19A,B . The differential diagnosis of this specimen included spindled squamous cell carcinoma, atypical fibroxanthoma, spindle cell melanoma, and...