Concordance between telepathologic diagnosis and conventional histopathologic diagnosis: a multiobserver store-and-forward study on 20 skin specimens

OBJECTIVE

To study the validity and feasibility of transferring images of cutaneous biopsy specimens via e-mail to remote physicians active in dermatopathology for teleconsultation.

DESIGN

Twenty skin specimens previously diagnosed at the Department of Dermatology, University of Graz, Austria, were subsequently sent for teleconsultation using the store-and-forward method. For each case, 3 or 4 images at different magnifications were sent by e-mail to 16 colleagues (11 dermatopathologists and 5 pathologists) in 15 centers in 6 different countries. Six weeks later each observer received the hematoxylin-eosin-stained specimens to render a conventional diagnosis.

SETTING

Dermatopathology and pathology units within institutional and private settings.

MATERIAL

Twenty small skin biopsy specimens of cutaneous diseases were selected randomly from a study set of 80.

MAIN OUTCOME MEASURE

Concordance between telepathologic diagnoses and conventional histopathologic diagnoses of 20 skin specimens.

RESULTS

On average, 78% of the telediagnoses were correct (range, 60%-95%), whereas 85% of the conventional diagnoses were correct (range, 60%-95%). A perfect diagnostic concordance was obtained in 7 (35%) of 20 cases, and a significant difference was identified in only 1 case.

CONCLUSIONS

Results suggest that telepathology performed by physicians active in dermatopathology may serve as a reliable technique for the diagnosis of cutaneous diseases when experts in dermatopathology are not available locally. Furthermore, teledermatopathology is attractive because it provides an opportunity to obtain timely consultation on difficult cases.

[Invisible dermatosis]

The microscopically "invisible dermatoses" comprise a heterogeneous plethora of skin disorders which are characterized by a stunning discrepancy between the classical clinical findings and very discrete histological alterations suggesting "normal skin." Methods and strategies for the correct histopathological diagnosis of seemingly normal skin are discussed.

Tissue counter analysis of histologic sections of melanoma: influence of mask size and shape, feature selection, statistical methods and tissue preparation

BACKGROUND

Tissue counter analysis is an image analysis tool designed for the detection of structures in complex images at the macroscopic or microscopic scale. As a basic principle, small square or circular measuring masks are randomly placed across the image and image analysis parameters are obtained for each mask. Based on learning sets, statistical classification procedures are generated which facilitate an automated classification of new data sets.

OBJECTIVE

To evaluate the influence of the size and shape of the measuring masks as well as the importance of feature selection, statistical procedures and technical preparation of slides on the performance of tissue counter analysis in microscopic images. As main quality measure of the final classification procedure, the percentage of elements that were correctly classified was used.

STUDY DESIGN

HE-stained slides of 25 primary cutaneous melanomas were evaluated by tissue counter analysis for the recognition of melanoma elements (section area occupied by tumour cells) in contrast to other tissue elements and background elements. Circular and square measuring masks, various subsets of image analysis features and classification and regression trees compared with linear discriminant analysis as statistical alternatives were used. The percentage of elements that were correctly classified by the various classification procedures was assessed. In order to evaluate the applicability to slides obtained from different laboratories, the best procedure was automatically applied in a test set of another 50 cases of primary melanoma derived from the same laboratory as the learning set and two test sets of 20 cases each derived from two different laboratories, and the measurements of melanoma area in these cases were compared with conventional assessment of vertical tumour thickness.

RESULTS

Square measuring masks were slightly superior to circular masks, and larger masks (64 or 128 pixels in diameter) were superior to smaller masks (8 to 32 pixels in diameter). As far as the subsets of image analysis features were concerned, colour features were superior to densitometric and Haralick texture features. Statistical moments of the grey level distribution were of least significance. CART (classification and regression tree) analysis turned out to be superior to linear discriminant analysis. In the best setting, 95% of melanoma tissue elements were correctly recognized. Automated measurement of melanoma area in the independent test sets yielded a correlation of r=0.846 with vertical tumour thickness (p<0.001), similar to the relationship reported for manual measurements. The test sets obtained from different laboratories yielded comparable results.

CONCLUSIONS

Large, square measuring masks, colour features and CART analysis provide a useful setting for the automated measurement of melanoma tissue in tissue counter analysis, which can also be used for slides derived from different laboratories.

Benign fibrous histiocytoma (dermatofibroma) of the face: clinicopathologic and immunohistochemical study of 34 cases associated with an aggressive clinical course

Thirty-four cases of fibrous histiocytoma (dermatofibroma) arising on the face are reported. These neoplasms occurred frequently in females (24 female, 10 male) and showed a broad age range (12 to 85 years; mean: 43.6 years, median: 41 years). The neoplasms originated on the forehead (nine cases), the cheek (eight cases), the eyebrow (four cases), the temporal region (three cases), the nose (two cases), and the ear (one case); in seven cases the location face was given only. Five of 27 cases with follow-up information (median: 5 years) recurred locally; in one case four recurrences were excised within 8 years. The majority of cases extended into the subcutis and deep soft tissue including striated muscle (50% of cases). Histologically, only the minority of cases was composed entirely of histiocytoid and spindle-shaped tumor cells arranged in a storiform growth pattern. In many cases cellular fascicles and bundles of spindle-shaped tumor cells were noted in addition to classical morphological features of fibrous histiocytoma. A moderate mitotic rate (mean: 2.97 mitoses in 10 HPFs) was observed, and in few cases increased atypia was evident. Frank tumor necrosis and/or vascular invasion were not identified. Immunohistochemical studies revealed Factor XIIIa positivity in 13 out of 17, focal CD68 positivity in 6 out of 10, and alpha-smooth muscle actin positivity in 16 out of 19 cases tested. These lesions should be distinguished from dermatofibrosarcoma protuberans, including its fibrosarcomatous variant, leiomyosarcoma, and low-grade myofibroblastic sarcoma. Cases of fibrous histiocytoma of the face have to be excised with wider margins in comparison with examples of classical fibrous histiocytoma occurring on the extremities because of diffuse infiltration, involvement of deeper structures, and an increased rate of local recurrences.

Epithelioid blue naevus of the genital mucosa: report of four cases

Epithelioid blue naevi are an unusual cytological variant of blue naevus that have been recently described mostly in patients with the Carney complex, although they may also occur in isolation. This variant of blue naevus is composed of melanin-laden polygonal epithelioid melanocytes situated within the dermis. The neoplastic cells show no maturation with progressive depth of dermal infiltration and, in contrast with the usual stromal changes in blue naevi, epithelioid blue naevi exhibit no dermal fibrosis. We describe four cases of epithelioid blue naevus located on the genital mucosa in four patients with no evidence of the Carney complex. Three male patients showed an epithelioid blue naevus on the mucosa of the glans penis and a female patient had a lesion of the right labium minoris. Histopathologically, the lesions consisted of entirely intradermal melanocytic naevi composed mostly of heavily pigmented epithelioid melanocytes involving the dermis of the genital mucosa. Immunohistochemically, in all cases, epithelioid melanocytes expressed immunoreactivity for S-100 protein, HMB-45, Melan-A and MiTF antibodies.

Dendritic cell neurofibroma with pseudorosettes: a report of 18 cases of a distinct and hitherto unrecognized neurofibroma variant

The authors present 18 cases of a hitherto unrecognized variant of cutaneous neurofibroma. The tumors presented in adults (10 occurred in men and eight occurred in women) as a solitary, well-circumscribed, superficial lesion located in the dermis measuring 3 to 17 mm (mean size, 6.2 mm). The tumors formed oval-shaped masses that ran perpendicular to the epidermis. In the deep part of the tumor there was multinodular arrangement with two types of cells: Type I cells were small, dark, lymphocyte-like cells with a slightly irregular nucleus and inconspicuous cytoplasm. Type II cells were larger, with pale-staining vesicular nuclei, with frequent invaginations and intranuclear inclusions, and had copious clear eosinophilic cytoplasm that formed a stellate growth pattern, which was poorly visible on hematoxylin and eosin staining. Type I cells were grouped concentrically around type II cells and formed pseudorosettes. Most of the type I and type II cells were S-100 protein and CD57 positive, and various proportions of both cell types were CD56 and PGP9.5 positive. All cells were chromogranin A, synaptophysin, glial fibrillary acidic protein, cytokeratins, CD1a, CD21, CD31, alpha-smooth muscle actin, muscle-specific actin, desmin, and HMB-45 negative. CD34 stained intralesional fibroblasts. Antibody to epithelial membrane antigen stained only the perineurium around the tumor masses, suggesting that the tumors arose inside the nerve sheath. No signs of neurosecretory granules were present at ultrastructural level. None of the lesions recurred and none metastasized over a mean follow-up of 8.1 years.

Cutaneous myoepithelioma: an under-recognized cutaneous neoplasm composed of myoepithelial cells

Benign and malignant neoplasms of myoepithelial cells comprise a rare but well-characterized group of tumors, among which myoepithelioma of the salivary glands is the best known. Extrasalivary examples of myoepithelioma also have been described in the breast, larynx, and retroperitoneum. Recently, myoepithelioma of the soft tissue also has been reported. According to this description, myoepithelioma and mixed tumors arising in the skin and subcutis represent points along a clinicopathologic spectrum of cutaneous and soft-tissue tumors. To the best of our knowledge, there has been only one case report of an entirely cutaneous myoepithelioma in the literature. We report herein five additional examples of purely myoepithelial tumors located exclusively in the dermis. Histopathologically, the neoplasms were well-circumscribed dermal lesions composed of fascicles of spindle cells with eosinophilic cytoplasm and ovoid-to spindle-shaped nuclei. Focally, neoplastic aggregations of more epithelioid cells representing large round cells with abundant pale cytoplasm arranged in solid clusters, cords, or strands were also seen. Ductal differentiation was not identified in either of these solid aggregations of epithelioid cells or in the fascicles of spindle-shaped cells. Nuclear pleomorphism in epithelioid and spindle-cell areas was mild, and mitotic figures were very sparse. In some cases, small, necrotic areas were seen within the solid aggregations of spindle-shaped cells. Neoplastic stroma was scant and composed of fibrillary collagen and abundant mucin. In one case, the stroma consisted of clusters of mature adipocytes intermingled with fascicles of myoepithelial cells. Areas of chondroid or osteoid metaplasia were not seen in any of the cases. Immunohistochemically, neoplastic cells expressed positivity for muscle specific actin (HHF35), alpha smooth muscle actin (IA4), S-100 protein, glial fibrillary acidic protein (GFAP), and epithelial membrane antigen (EMA), whereas stains for pan-cytokeratin (MNF116) were focal and weak. The findings in this report expand the clinical and histopathologic spectrum of cutaneous myoepithelioma, an under-recognized cutaneous neoplasm of myoepithelial cells.

Lymphomatoid papulosis and human herpesviruses--A PCR-based evaluation for the presence of human herpesvirus 6, 7 and 8 related herpesviruses

BACKGROUND

Lymphomatoid papulosis (LyP) is a chronic, recurrent lymphoproliferative disorder of the skin that belongs to the group of primary cutaneous CD30-positive T-cell lymphomas. Ultrastructural and clinical features of LyP suggest that it has a viral etiology. Human herpesviruses have been proposed as causative cofactors for LyP because of their oncogenic potential and their association with other lymphomas.

METHODS

LyP skin lesions and a LyP-derived cell line were examined for the presence of the recently discovered oncogenic human herpesvirus 8 (HHV-8) and the two T-lymphotropic human herpesviruses 6 and 7 (HHV-6 and HHV-7) by nested polymerase chain reaction (PCR) using virus-specific oligonucleotide primers. Furthermore, a recently described method involving degenerate PCR primers was applied to detect highly conserved DNA sequences shared by a variety of herpesviruses, especially oncogenic gamma-herpesviruses, in an attempt to identify a yet undiscovered herpesvirus associated with LyP.

RESULTS

HHV-6 and 8 could not be found in 26 archival and 11 snap-frozen LyP lesions and a LyP tumor cell line. HHV-7 DNA sequences were detected in 14% (5 of 37) of LyP samples. HHV-6 was found in 23% (3 of 13) and HHV-7 in 8% (1 of 13) of normal skin samples from healthy individuals, respectively. Using degenerate PCR primers to amplify the highly conserved polymerase region of herpesviruses, no DNA sequences related to human herpesviruses could be detected.

CONCLUSIONS

LyP is not associated with HHV-6, HHV-7 and HHV-8. In addition, the studies using degenerate PCR primers do not indicate the presence of a previously undescribed human herpesvirus in LyP.

Intradermal spindle cell/pleomorphic lipoma: a distinct subset

Spindle cell/pleomorphic lipomas are a group of benign lipogenic tumors composed of primitive spindle cells, multinucleated giant cells, and mature adipocytes. These tumors have rarely been reported to arise in the dermis and may be misdiagnosed in this location. Twenty (12.7%) intradermal lesions identified among 157 spindle cell/pleomorphic lipomas in the authors' files were studied clinicopathologically and immunohistochemically. The patients' ages ranged from 20 to 85 years (median: 42 years); 14 of 20 patients were female (70%). Anatomical sites were the head/neck region (7 cases, 4 of which arose on the face), shoulder/upper back (4 cases), lower limbs (4 cases), trunk (3 cases), and upper limbs (2 cases). Most lesions presented as a soft and slowly enlarging cutaneous nodule, usually measuring less than 2.5 cm. Histologically, these dermal lesions differed from usual spindle cell/pleomorphic lipoma, being unencapsulated with poorly defined infiltrative margins, although the cytomorphologic findings, ropy collagen, and mast cells were as seen in usual subcutaneous lesions. Six cases showed features of pleomorphic lipoma. Immunohistochemically, lesional cells stained positively for CD34 and were negative for S-100 protein. One case recurred locally after 21 years. Dermal spindle cell/pleomorphic lipomas are distinctive in their apparent female predilection, wider anatomical distribution than subcutaneous lesions, and lack of circumscription. These unusual features can cause problems in differential diagnosis.

Allelic deletion at 9p21-22 in primary cutaneous CD30(+) large cell lymphoma

The genetic alterations responsible for the development of cutaneous lymphoma are largely unknown. Chromosome region 9p21 contains a gene locus encoding an inhibitor of cyclin-dependent kinase 4, and heterozygous deletions of this tumor suppressor gene (p16) have been shown in a variety of malignant tumors. We studied 11 randomly selected cutaneous CD30-positive large cell lymphomas. Several areas containing 20-50 CD30-positive lymphocytes were microdissected in each case and subjected to single-step DNA extraction. Loss of heterozygosity analysis was performed using polymorphic markers at 9p21 (IFNA, D9S171, D9S169) and 17p13 (TP53). Samples from normal cells apart from CD30-positive lymphocytes, e.g., CD30-negative lymphohistiocytic infiltrates and normal epidermal layer, were also obtained in all cases from the same slide for comparison with the tumor samples. Expression of CD30 and T-lineage antigens (CD3, CD45Ro) was confirmed in all cases. Immunohistochemical staining for p16 and p53 was performed using the monoclonal antibodies sc-1661 and DO-7, respectively. Of the 11 informative cases, seven (64%) exhibited loss of heterozygosity at least for one marker at 9p21 (p16), whereas no allelic deletions were found for the polymorphic marker at 17p13 (p53). On immunohistochemistry loss of the p16 protein was detected in two of 11 cases. Nuclear staining for p53 protein was found in four of 11 cases. Here, we provide the first evidence of the involvement of the tumor suppressor gene p16 in primary cutaneous large cell lymphoma. Whether p16 deletion in these lymphomas is associated with disease progression and whether this method could serve as an early marker to detect lymphomas at an early stage needs to be addressed in future studies. J Invest Dermatol 115:1104-1107 2000

[Symplastic hemangioma]

BACKGROUND AND OBJECTIVE

Endothelial nuclear atypia is the hallmark of malignant vascular tumors. Pleomorphic nuclei of the muscular vessel wall and the adventitia are manifestations of degenerative phenomena and should not be misinterpreted as signs of malignancy.

PATIENTS/METHODS

Three long-standing solitary superficial vascular tumors (61-year-old woman, 48- and 63-year-old men) were removed by primary excision. Sections were stained according to standard histologic and immunohistologic protocols.

RESULTS

Symplastic hemangiomas show the silhouette of a small superficial angioleiomyoma or capillary hemangioma. Characteristic features are multinucleate cells of the muscular vessel wall and the adventitia with pleomorphic nuclei, broad hyalinized vessel walls, and the distinctive lack of endothelial nuclear atypia. Recurrences or metastases were not reported (follow-up of 9, 45 and 90 months).

CONCLUSIONS

Symplastic hemangioma is a benign superficial hemangioma with histological features of a pseudomalignancy. The distinctive lack of endothelial nuclear atypia allows distinction from malignant vascular tumors.

Epithelioid blue nevus: a rare variant of blue nevus not always associated with the Carney complex

Epithelioid blue nevus is a rare variant of blue nevus that has been recently described in patients with Carney complex. Some of the patients with Carney complex have multiple epithelioid blue nevi and a familial history of similar lesions is often recorded. Epithelioid blue nevus consists of an intradermal melanocytic nevus composed of polygonal epithelioid cells laden with melanin. Neoplastic cells show no maturation at the base of the lesion and, in contrast with the usual stromal changes in blue nevi, epithelioid blue nevus exhibits no fibrosis of the dermis. We have studied three cases of epithelioid blue nevus in three patients with no evidence of Carney complex. The lesions were solitary and there was no family history of similar lesions. Therefore, epithelioid blue nevus is a distinctive variant of blue nevus that may also appear as a sporadic lesion and is not always associated with Carney complex.

Epithelial sheath neuroma: a new entity

The authors describe four examples of a peculiar cutaneous lesion characterized histopathologically by a proliferation of enlarged nerve fibers ensheathed by squamous epithelium involving the superficial dermis. The perineural epithelial sheaths were composed of uniform squamous epithelium with evidence of cornification in the form of dyskeratotic cells or resulting in orthokeratotic basket-weave corneocytes. Immunohistochemical studies confirmed the epithelial and neural nature of the two components of the lesions, with the nerve fibers expressing immunoreactivity for S-100 protein, neurofilaments, CD57, and nerve growth factor receptor, whereas the perineural epithelial sheaths showed immunoreactivity for cytokeratins. The authors propose the term "epithelial sheath neuroma" for this lesion and believe that it is a distinct and a previously undescribed benign neoplasm of both cutaneous nerves and epithelial elements.

Papular-purpuric "gloves and socks" syndrome: polymerase chain reaction demonstration of parvovirus B19 DNA in cutaneous lesions and sera

We report a typical case of papular-purpuric "gloves and socks" syndrome (PPGSS) in which primary infection by parvovirus B19 was demonstrated by seroconversion to this virus; parvovirus B19 DNA was also identified by polymerase chain reaction (PCR) methods in the sera of the patient and in the cutaneous biopsy specimen, both taken 4 days after the onset of clinical manifestations. To our knowledge, this is the fourth published case in which parvovirus B19 DNA has been recovered from the skin by PCR. Serologic studies and PCR investigations in cutaneous biopsy for other viruses including herpes simplex virus types 1 and 2, varicella zoster virus, Epstein-Barr virus, cytomegalovirus, and human herpesvirus 6, 7, and 8 were negative. Clinically, our case presented some additional features, which have not been previously described in cases of PPGSS, namely dysuria with vulvar edema and erythema, and unilateral petechial rash on the breast. The histopathologic findings of our case were nonspecific and consisted of an interface dermatitis with slight vacuolar degeneration at the dermoepidermal junction and a superficial perivascular inflammatory infiltrate mostly composed of lymphocytes, with numerous extravasated erythrocytes. We review the cases of PPGSS published in the literature with respect to the different viruses that have been proposed as etiologic agents and conclude that acute infection by parvovirus B19 is the only one that has been adequately proved.

Signet-ring cell formation in cutaneous neoplasms

BACKGROUND

Signet-ring cells are formed by intracytoplasmic accumulations of various substances that push the nucleus to the cellular border. Signet-ring cells in epithelial neoplasms are often regarded as evidence of adenocarcinoma.

OBJECTIVE

The study surveys the rare settings in which signet-ring cells are encountered in dermatopathologic specimens and investigates mechanisms of their formation.

METHODS

A total of 23 cutaneous tumors with a significant population of signet-ring cells were studied by immunohistochemistry and electron microscopy.

RESULTS

Signet-ring cells were found in a variety of cutaneous neoplasms, including primary cutaneous squamous and basal cell carcinoma and melanoma, as well as in metastatic adenocarcinoma. In all but the metastatic adenocarcinomas the vacuoles were periodic acid Schiff (PAS), PAS-digest, and colloidal iron negative. There was no staining of the vacuoles with antibodies against keratins and vimentin. Electron microscopy showed only empty spaces in all cases.

CONCLUSION

The signet-ring like appearance of the cells in most of these conditions is probably the result of coalescence of intracytoplasmic vacuoles and not accumulation of secretory products. Signet-ring formation is not specific for cellular lineage but can occur in a variety of cutaneous neoplasms, analogous to other cellular alterations as rhabdoid, granular, clear, spindle, and balloon cells and oncocytes.

Cystic sebaceous tumors as marker lesions for the Muir-Torre syndrome: a histopathologic and molecular genetic study

Cystic sebaceous tumors (CST) are well-circumscribed, large, deeply located dermal sebaceous proliferations with a cystic growth pattern. We identified 12 CST in 8 of 19 patients with Muir-Torre syndrome (MTS). We interpret CST as a tumor spectrum with clearly benign cystic sebaceous adenomas at one end and proliferative atypical cystic sebaceous tumors at the other. When examining these proliferative atypical tumors on morphologic criteria alone, the possibility of an evolving cystic sebaceous carcinoma cannot be excluded. We have not observed recurrences or metastases, indicating that these lesions are not highly malignant carcinomas. In 10 of 12 cases of CST, we examined microsatellite instability (MSI). All 10 examined examples of CST from patients with MTS showed MSI characteristic for hereditary nonpolyposis colorectal cancer (HNPCC), which is caused by autosomal dominant inherited DNA mismatch repair (MMR) defects. Mutational analysis of the MMR genes hMSH2 and hMLH1 had revealed different germline mutations in the hMSH2 gene in three of six examined patients with MTS with CST. We then found four more CST in patients without a history of internal malignancy. All four CST exhibited MSI. By mutational analysis in one of these patients we identified a truncating germline mutation in the MMR gene hMLH1. We conclude that CST is a marker for the mismatch repair-deficient subtype of MTS with a high risk for later internal malignancies. By recognizing CST, the histopathologist can suggest the great likelihood of MTS to the clinician.

Hobnail hemangioma ("targetoid hemosiderotic hemangioma"): clinicopathologic and immunohistochemical analysis of 62 cases

Hobnail hemangioma, also known as "targetoid hemosiderotic hemangioma", represents a distinctive, benign vascular tumor, characterized histologically by a biphasic growth pattern of dilated vascular structures in the superficial dermis lined by prominent hobnail endothelial cells, and collagen dissecting, rather narrow neoplastic vessels in deeper parts of the lesion. We analyzed the clinicopathologic and immunohistochemical features in a series of 62 cases. Patient age range was 6-72 years (median: 32 years); 34 patients were male and 25 female. Clinically, a broad variation of diagnoses ranging from hemangioma to dermal melanocytic nevus and fibrous histiocytoma was suggested. Nineteen tumors arose in the lower and 13 in the upper extremities, 12 on the back, 8 in the buttock and hip region, and one case on the chest wall. Follow-up information on 35 patients (range from 1 to 4 years; mean: 1.5 years) revealed no local recurrence nor systemic metastasis. All neoplasms were located in the dermis and showed a broad morphologic spectrum in dependence of the age of the lesions. In addition to lesions resembling cavernous lymphangioma or lymphangioma circumscriptum, neoplasms were seen with morphologic features reminiscent to retiform hemangioendothelioma, progressive lymphangioma and so-called Dabska's tumor. Immunohistochemistry performed in 28 cases showed positive staining of tumor cells for CD31 in all cases tested, whereas only 3 out of 28 cases stained completely positive for CD34. In addition 4 out of 8 cases stained positively for vascular endothelial growth factor receptor-3 (VEGFR-3). Neoplastic endothelial cells were surrounded by actin-positive pericytes in only 7 out of 27 cases tested. Hobnail hemangioma occurs more frequently in male patients and arises commonly in the extremities and the trunk. Histologic and immunohistochemcial features suggest a lymphatic line of differentiation for this distinctive vascular neoplasm.

Methotrexate-induced papular eruption in patients with rheumatic diseases: a distinctive adverse cutaneous reaction produced by methotrexate in patients with collagen vascular diseases

BACKGROUND

In the past few years, low doses of methotrexate have been used for treatment of patients with rheumatoid arthritis and other collagen vascular diseases, mainly as an immunosuppressive and corticosteroid-sparing drug. Several cutaneous adverse reactions have been described in association with methotrexate therapy.

OBJECTIVE

We describe the clinical and the histopathologic features of distinctive cutaneous lesions that appeared in 4 patients with acute bouts of collagen vascular diseases who were receiving methotrexate therapy.

METHODS

We clinically and histopathologically evaluated cutaneous lesions caused by methotrexate therapy in 4 patients, 2 with systemic lupus erythematosus, 1 with rheumatoid arthritis, and 1 with Sharp syndrome.

RESULTS

Clinically, lesions consisted of erythematous indurated papules most commonly located on proximal areas of the extremities. Histopathologic examination of these papules showed an inflammatory infiltrate mainly composed of histiocytes interstitially arranged between collagen bundles of the dermis, intermingled with few neutrophils. In some foci of deeper reticular dermis, small rosettes composed of clusters of histiocytes surrounding a thick central collagen bundle were seen. Cutaneous lesions showed a direct chronologic relationship with methotrexate therapy, and they disappeared when the drug was tapered or withdrawn and corticosteroids were increased.

CONCLUSION

Patients receiving low doses of methotrexate for acute bouts of collagen vascular diseases may experience characteristic cutaneous lesions with distinctive clinical and histopathologic findings shortly after methotrexate administration. We discuss the differential diagnosis with other dermatoses showing similar histopathologic findings that have been described in patients with collagen vascular diseases.

[Perivascular myoma: a new concept for "myofibroblastic" tumors with perivascular myoid differentiation]

The morphological spectrum of cutaneous adult myofibroma (AM) is presented which has been considered to be the adult counterpart of infantile myofibromatosis. 63 cases of AM were evaluated and various subtypes could be discerned: classical biphasic type with hyalinized basophilic spindle cell nodules and adjacent small primitive pericytic cells forming richly vascularized hemangiopericytomatous sheets; glomangiopericytoma with a predominant hemangiopericytomatous pattern and small glomoid-pericytic cells; myopericytoma with angiocentric proliferation of small pericytic cells; rare variants, e.g. solid myopericytoma, and sclerotic myofibroma. There is considerable morphological overlap, and the morphological spectrum certainly is much wider. It is suggested that these presumably myofibroblastic cutaneous tumors are derived from a pluripotent periendothelial cell capable of differentiating along smooth muscle, pericytic, and glomus cell lines. Following a recent proposal by Granter et al. (7) these tumors are re-classified as variants of perivascular myoma, a perivascular tumor with myoid differentiation. The role of the myofibroblast in these tumors is reevaluated. In order to determine whether perivascular myoma is composed of a clonal cell population as opposed to being a polyclonal reactive process, analysis of patterns of X-chromosome inactivation was performed. Clonality of the tissue was determined by analysing the methylation status of two different X-chromosome linked polymorphic markers: the phosphoglycerate kinase gene (PGK) and the human androgen receptor gene (HUMARA). Both methods are based on the amplification of differing gene loci in heterozygous women after digestion of the DNA with methylation sensitive restriction enzymes. Out of 20 investigated female tumors 10 tumors were non-informative, 7 tumors showed a uniform pattern of X-chromosome inactivation (clonal), 3 tumors remained heterozygous (polyclonal). It remains to be determined whether perivascular myoma is a true tumor or a reactive/hyperplastic process.

Solitary plaque-like telangiectatic glomangioma

We present a new clinicopathological variant of glomangioma. The lesion consisted of a painful solitary telangiectatic plaque on the right shoulder of a 33-year-old woman. It had been present for 3 years. Histopathology revealed ectatic vascular lumina within the dermis surrounded by glomus cells. Immunohistochemical and ultrastructural investigations confirmed the nature of the glomus cells. Acquired solitary plaque-like telangiectatic glomangioma is a new and distinctive variant of cutaneous glomus tumour.