[Immunohistochemical study of calretinin in normal hair follicles and tumors with follicular differentiation]

BACKGROUND

Selective immunostaining for calretinin labels the innermost layer of the outer root sheath of normal hair follicles, which is difficult to distinguish with hematoxylin-eosin staining.

OBJECTIVE

The aim of this study was to determine whether immunohistochemistry for calretinin allows identification of cutaneous adnexal tumors with follicular differentiation towards cells of the outer root sheath.

MATERIAL AND METHODS

We analyzed the staining pattern for calretinin by immunohistochemistry in 49 biopsies of cutaneous adnexal tumors with follicular differentiation.

RESULTS

Fifteen biopsies corresponded to trichilemmomas/inverted follicular keratosis and had staining for calretinin in the epithelium of the most superficial areas of the lesions and in squamous eddies. Ten were trichilemmal cysts, which displayed staining of the cyst wall. Three were basal cell carcinomas with variable staining according to the type of follicular differentiation in each variant. One was a panfolliculoma that had focal staining. Two were folliculosebaceous cystic hamartomas with staining of the excretory duct of the sebaceous glands. Two pilomatricomas and 3 proliferative trichilemmal tumors had positive staining in the cellular layers close to the lumen of the cystic structures. Nine trichoblastomas/trichoepitheliomas, 2 infundibular cysts, 1 dilated pore of Winer, and 2 acanthomas of the follicular sheath were negative for calretinin.

CONCLUSION

Immunohistochemistry for calretinin allows identification of cutaneous adnexal tumors of the hair follicle or a component of the follicle with differentiation towards cells of the outer root sheath.

Detection of spirochaetal microorganisms by focus floating microscopy in necrobiosis lipoidica in patients from central Europe

AIMS

Necrobiosis lipoidica (NL) is a chronic inflammatory skin disease with unknown aetiology. The aim was to determine the presence of spirochaetal microorganisms in NL.

METHODS AND RESULTS

Focus-floating microscopy (FFM) is a modified immunohistochemical technique that was developed to detect borrelial spirochaetes within tissue sections. It has proven to be more sensitive for the detection of spirochaetes than polymerase chain reaction (PCR). Fifty-six cases of NL as well as 44 negative and 33 positive controls were investigated for the presence of Borrelia within tissue specimens. Using FFM, Borrelia could be detected in 42 cases (75.0%) and were seen significantly more often in histologically active inflammatory-rich (38/41, 92.7%) than in inflammatory-poor (4/15, 26.7%) cases of NL (P < 0.001). Seven cases investigated with a Borrelia-specific PCR (23s-RNA) remained negative. In contrast, FFM was positive in 30 of 33 (90.9%) positive controls of acrodermatitis chronica atrophicans and 15 of the positive controls (45.5%) were also positive with PCR, whereas no negative controls revealed any microorganisms.

CONCLUSIONS

Detection of spirochaetes in NL points to a specific involvement of B. burgdorferi or other similar strains in the development of or trigger for this disease.

Cutaneous composite hemangioendothelioma with satellitosis and lymph node metastases

The term hemangioendothelioma has been used in recent years to name a heterogeneous group of vascular neoplasms, intermediate in both biological behavior and histopathologic appearance between benign tumors (hemangiomas) and frankly malignant tumors (angiosarcomas). Thus, within the spectrum of hemangioendothelioma have been successively included epithelioid hemangioendothelioma, spindle cell hemangioendothelioma, retiform hemangioendothelioma, kaposiform hemangioendothelioma, polymorphous hemagioendothelioma of the lymph nodes, papillary intralymphatic angioendothelioma (PILA) and composite hemangioendothelioma. The latter is a vascular neoplasm showing varying combinations of benign, low-grade malignant and malignant vascular components. We herein report a case of composite hemangioendothelioma showing a combination of retiform hemangioendothelioma, epithelioid hemangioendothelioma, spindle cell hemangioma and PILA. The neoplasm showed a more aggressive behavior than other reported cases of composite hemangioendothelioma and it developed satellitosis and metastases to the inguinal lymph nodes. Neoplastic cells expressed immunoreactivity for Prox-1, supporting a lymphatic line of differentiation.

Squamous cell apocrine hidradenoma

Apocrine hidradenoma is a benign adnexal neoplasm with apocrine differentiation. The neoplasm is composed of four different types of epithelial cells, including pale or clear cells, polygonal cells, mucinous cells and squamous cells, with variable proportions of them from case to case. In most examples of this neoplasm, clear or the polygonal cells are predominant, whereas the other types of neoplastic cells are less abundant. We report two cases of apocrine hidradenoma mostly composed of squamous cells. Histopathologic examination showed that the neoplasms were composed of both solid and cystic areas. The solid aggregations of neoplastic cells were composed of a peripheral layer of basaloid polygonal cells, whereas squamous cells forming the bulk of the aggregations. These squamous cells showed large eosinophilic cytoplasm and vesicular nuclei with prominent nucleoli. In one case, small foci of mucinous cells could also be seen in some aggregations of neoplastic cells, mostly around ductal structures. In both the cases, some of the tubular structures lined by epithelial cells showed evidence of decapitation secretion in their luminal border. The neoplastic stroma consisted of sclerotic collagen bundles when compared with adjacent normal dermis, and artefactual clefts separated the neoplasms from the surrounding tissue. The rare cases described in this report are exceptional because most of the neoplastic cells showed squamous appearance and for that reason we think that squamous cell apocrine hidradenoma is the most appropriate name for these neoplasms.

[Epithelioid and hyperpigmented melanocytic tumors. An overview]

Spindle cell and epithelioid cell differentiation occur in both benign and malignant hyperpigmented melanocytic lesions. Reed nevus is characterized by compact, sharply circumscribed junctional cellular nests composed of slender hyperpigmented melanocytes shaped like spindle cells. Deep penetrating nevus is characterized by a diffuse dermal proliferation composed of small nests and fascicles of pale ovoid and epithelioid melanocytes. Cellular blue nevi often have a characteristic hourglass or dumbbell shape, with sharply circumscribed elongated nests and fascicles of pale, densely layered ovoid melanocytes and adjacent melanophages. Epithelioid blue nevus is characterized by large epithelioid melanocytes with abundant cytoplasm and melanin often concentrated to some degree in the cell membrane. Animal-type melanoma is a particularly hyperpigmented variant of melanoma in which large melanophages predominate and there are varying proportions of melamin-rich spindle-shaped and large atypical epithelioid melanocytes. Morphologically, pigmented epithelioid melanocytoma combines characteristics of both animal-type melanoma and pigmented epithelioid nevus. Malignant melanoma may occur in conjunction with a preexistent blue nevus. Malignant blue nevus is now regarded as a malignant melanoma mimicking a blue nevus in structure and pattern. It is therefore of paramount importance to view multiple mitoses within a cellular blue nevus-like proliferation as an alarm signal as they are usually indicators of a malignant melanoma.

Apocrine mixed tumor of the skin (“mixed tumor of the folliculosebaceous-apocrine complex”)

BACKGROUND

A systematic analysis of the entire spectrum of various forms of differentiation and metaplastic epiphenomena in cutaneous apocrine mixed tumor (AMT) has never been performed.

OBJECTIVE

The purpose of our study was to study a large number of cutaneous mixed tumors so as to fully characterize the entire spectrum of differentiations and metaplastic changes that may occur in the epithelial, myoepithelial, and stromal components of AMT.

METHODS

This article reports a light-microscopic study of 244 cases of cutaneous AMT, complemented by a literature review.

RESULTS

All types of differentiation along the lines of the folliculosebaceous-apocrine unit can be seen in AMT. The spectrum of metaplastic changes in the epithelial components includes squamous metaplasia, mucinous metaplasia, oxyphilic metaplasia, clear cell change, columnar metaplasia, hobnail metaplasia, and cytoplasmic vacuolization. The following changes in the myoepithelial component were documented: clear cell change, hyaline cells, plasmacytoid cells, spindling, and collagenous spherulosis. Stromal alterations included chondroid metaplasia, osseous metaplasia, and adipose metaplasia.

LIMITATIONS

This study utilizes tissue specimens that mainly came as consultations; therefore some inherent selection bias exists.

CONCLUSIONS

AMT displays a wide range of differentiation and metaplastic changes in its epithelial, myoepithelial, and stromal components. These phenomena are not mutually exclusive. When unduly prominent, they may present diagnostic pitfalls. Our findings corroborate those of previous publications, stressing the remarkable diversity of differentiation and metaplasias that may be found in cutaneous AMT. We propose that the most appropriate name for these lesions is "mixed tumor of the folliculosebaceous-apocrine complex."

Optimierung der dermatopathologischen Diagnostik durch digitale Fotografie und Internet

Clinicopathologic correlation is the basis of a precise diagnosis. Especially in dermatopathology, the precision of a microscopic diagnosis may significantly be increased by thorough knowledge of the clinical picture. The advent of digital photography, the internet and moderately priced CDs and USB-sticks have made it possible to establish and maintain a time-saving, low-cost picture data transfer between dermatologist and dermatopathologist which is optimally suited for clinicopathologic correlation.

Sarcoidal granulomatous tenosynovitis of the hands occurring in an organ transplant patient

Six years after kidney-pancreas transplant, a 47-year-old white man developed multiple subcutaneous and tenosynovial nodules of hands and wrists, limiting mobility. Biopsy of multiple nodules showed fibrosing, sarcoidal granulomas, some of which contained pigmented material. Microbiology, immunohistochemistry, scanning electron microscopy with backscattered electron imaging and energy dispersive X-ray analysis and polymerase chain reaction assays failed to show any infectious agents or foreign material. There was no historical, clinical or laboratory evidence of systemic sarcoidosis. It is not known whether the donor had sarcoidosis. Despite empiric antimycobacterial therapy and ongoing immunosuppressive therapy (corticosteroids, mycophenolate, cyclosporine), the man has progressively developed more nodules, limiting hand function. Sarcoidosis occurring in non-donor tissue post-transplantation is an exceedingly rare complication of transplantation. We discuss this case and review the literature on sarcoidal tenosynovitis and sarcoidosis occurring post-transplantation.

Pseudolymphomatous Cutaneous Angiosarcoma: A Rare Variant of Cutaneous Angiosarcoma Readily Mistaken for Cutaneous Lymphoma

Cutaneous angiosarcoma is probably the most malignant neoplasm involving the skin. Three clinical variants of cutaneous angiosarcoma are recognized, including angiosarcoma of the scalp and face of elderly patients, angiosarcoma associated with chronic lymphedema, and postirradiation angiosarcoma. Histopathologically, these three variants of angiosarcoma show similar features, which consist of poorly circumscribed, irregularly dilated, and anastomosing vascular channels lined by prominent endothelial cells that dissect through the dermis. Focally, neoplastic endothelial cells show large, hyperchromatic, and pleomorphic nuclei, protruding within vascular lumina and creating small papillations. Usually, inflammatory infiltrate is sparse and consists of a patchy, perivascular lymphoid infiltrate around the neoformed vessels. In rare instances, cutaneous angiosarcomas may exhibit prominent inflammatory infiltrate, and the neoplasm may be mistaken for an inflammatory process, both from clinical and histopathologic points of view. We describe four examples of cutaneous angiosarcomas with dense lymphocytic infiltrates involving the neoplasm. Immunohistochemically, lymphocytes expressed immunoreactivity for CD3, CD5, and CD45 markers, whereas the germinal centers were positive for CD20, CD79a, and Bcl-6. The neoplastic endothelial cells expressed immunoreactivity for the CD31, CD34, podoplanin, Prox-1, Lyve-1, and D2-40. We discuss the possible relationship between neoplastic endothelial lymphatic cells and reactive lymphocytes. Cutaneous angiosarcoma with prominent lymphocytic infiltrate may be readily mistaken for cutaneous follicle center cell lymphoma or cutaneous pseudolymphoma.

Tubular adenoma and syringocystadenoma papilliferum: a reappraisal of their relationship. An interobserver study of a series, by a panel of dermatopathologists

Tubular adenoma (TA) and syringocystadenoma papilliferum (SCAP) may show histopathological overlap, with some lesions having features of both neoplasms (SCAP + TA). TA has been recently suggested to represent a carcinoma. Four observers blindly assessed 67 cases of TA, SCAP, and their lookalikes (poroma, apocrine adenoma, apocrine carcinoma; all lesions focally featuring a pseudopapillary pattern), and classified the lesions into one of four categories: (1) TA, (2) SCAP, (3) SCAP + TA, and (4) others. Lesions were also classified as benign or malignant. In only 29 cases was there unanimous agreement among the four observers, who classified 22 lesions as TA, three as SCAP, and four cases as others. Of the 38 cases where there was interobserver diagnostic variation, in 30, the diagnosis varied between TA or SCAP or SCAP + TA; the remainder fell in the others category. Analysis of the factors leading to interobserver variability indicated that diagnostic problems occurred when there were any of the following: epidermal acanthosis, papillomatosis, connection of the neoplastic tubules to the overlying epidermis and/or follicular infundibula, and plasma cell infiltration. These features accounted for the morphological overlap between TA and SCAP. All observers agreed that the lesions were benign; the only apocrine carcinoma included was recognized as such by all observers. From the study, it was concluded that TA may arise in the deep dermis without any epidermal connection, or, in other cases, it may be more superficially located with or without an epidermal connection. It may be reasonably inferred that, possibly as a response to infection, there may be accompanying plasma cells and variable acanthosis and papillomatosis, such that the appearances are those of "pure" SCAP, or lesions may have features "intermediate" or overlapping between TA and SCAP.

Apocrine Mixed Tumors of the Skin With Architectural and/or Cytologic Atypia: A Retrospective Clinicopathologic Study of 18 Cases

We present a series of 18 atypical apocrine mixed tumors of the skin characterized by architectural and/or cytologic atypia but which nevertheless do not qualify these lesions as carcinomas. There were 15 males and 3 females, and all but 1 presented with solitary nodules ranging in size from 4 to 20 mm; 1 female had a large tumor of 12 cm. The tumors were preferentially located on the head area, especially the face (13 cases). Other locations included the lower extremities (3) and inguinal area (2). In all patients, surgical excision of the tumors was performed. Clinical follow-up was available in 11 cases and ranged from 1 to 24 years (mean 9.6 y; median 5 y). No recurrences or metastases were documented. Overall, the lesions manifested a rather benign architecture, usually with good circumscription, lack of capsular breach or hypercellularity; however, some asymmetry, focally irregular infiltrationlike or pushing tumorous borders were seen. Microscopically, 17 cases conformed to the so-called hyaline cell-rich variant and showed multinucleated, bizarre, hyperchromatic cells in hyaline cell areas that had a myoepithelial immunophenotype; in 1 case, atypical mitotic figures were noted. One case showed mild nuclear pleomorphism in the ductal component. Tumors were negative for p53, including bizarre giant cells that did not label with Ki-67. Ultrastructurally, hyaline cells exhibited features consistent with myoepithelial differentiation. Seven cases studied by immunohistochemistry proved negative for HER-2/neu (c-erbB-2) protein expression, and the HER-2/neu gene was not amplified by fluorescence in situ hybridization analysis in 5 cases tested. As controls, 4 authentic malignant mixed tumors were studied, but these likewise tested negative for HER-2/neu protein expression and showed no gene amplification; 1 malignant mixed tumor had polysomy 17. We conclude that some atypical cytoarchitectural features in apocrine mixed tumors, albeit worrisome, do not indicate a malignant change.

Primary Cutaneous Marginal Zone B-cell Lymphoma May Exhibit Both the t(14;18)(q32;q21) IGH/BCL2 and the t(14;18)(q32;q21) IGH/MALT1 Translocation: An Indicator for Clonal Transformation Towards Higher-Grade B-cell Lymphoma?

Primary cutaneous marginal zone B-cell lymphoma (PCMZL) is a recently proposed entity and constitutes the cutaneous counterpart of extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT). The t(14;18)(q32;q21) involving the IGH and the MALT1 gene has previously been described in PCMZL, whereas the t(14;18)(q32;q21) IGH/BCL2 seems to be restricted to follicular lymphoma and diffuse large B-cell lymphoma. We screened 30 PCMZLs of 13 patients by fluorescent in situ hybridization analysis for the presence of the t(14;18)(q32;q21) IGH/BCL2 and the t(14;18)(q32;q21)IGH/MALT1. The t(14;18)(q32;q21) IGH/MALT1 was detected in 10 PCMZLs of eight patients, with four patients showing the t(14;18)(q32;q21) IGH/MALT1 exclusively. The t(14;18)(q32;q21)IGH/BCL2 was detected in 16 PCMZLs of seven patients, with four patients showing the t(14;18)(q32;q21) IGH/BCL2 exclusively. Six lymphomas of four patients showed both translocations in the same lesion. In seven lymphomas, neither of the two translocations occurred. One patient developed multiple lesions without either of the two translocations. Our results underline that both the t(14;18)(q32;q21)IGH/BCL2 and the t(14;18)(q32;q21) IGH/MALT1 may occur in PCMZL, albeit in an irregular distribution. Therefore, the etiopathogenetic relevance of either translocation in PCMZL remains a matter of debate.

Generalized livedo reticularis associated with monoclonal cryoglobulinemia and multiple myeloma

Cryoglobulins are detected in a wide variety of diseases, including malignancies, infections and systemic autoimmune diseases. Classically, monoclonal cryoglobulinemia is associated with hematologic malignancies, whereas mixed cryoglobulinemias are reported in association with hepatitis C virus infections or autoimmune diseases. We present a patient with generalized livedo reticularis as the first manifestation of monoclonal cryoglobulinemia and multiple myeloma. Histopathology demonstrated that nearly all small blood vessels of the upper and deep dermis, as well as the capillaries of the fat lobule, were filled with homogeneous, eosinophilic material that corresponded to monoclonal cryoglobulin deposits within the vascular lumina. Our case of livedo reticularis associated with monoclonal cryoglobulinemia and multiple myeloma was exceptional, because the mottled cyanotic discoloration of the skin with a reticular pattern was generalized, covering most of the skin surface. We have not found previous report of similar cases. Therefore, we recommend that dermatologists be made aware of the significance of this diagnosis.

Localized panniculitis secondary to subcutaneous glatiramer acetate injections for the treatment of multiple sclerosis: A clinicopathologic and immunohistochemical study

BACKGROUND

Glatiramer acetate has been shown to be effective in reducing the relapse and improving the disability of patients with multiple sclerosis. The most common adverse effects at the injection sites include pain, inflammation, and induration that spontaneously disappear within hours or a few days.

OBJECTIVE

We sought to characterize the histopathologic findings of localized panniculitis induced by glatiramer acetate at the injection sites.

METHODS

Seven patients receiving daily glatiramer acetate injections for treatment of multiple sclerosis developed localized panniculitis at the injection sites. The lesions were histopathologically and immunohistochemically studied.

RESULTS

The lesions consisted of a mostly lobular panniculitis, with lipophagic granuloma, namely histiocytes engulfing the lipids from necrotic adipocytes. In many areas, scattered neutrophils and eosinophils were seen both in the septa and in the fat lobules. Connective tissue septa showed widening and fibrosis in conjunction with many lymphoid follicles, presenting with germinal center formation. Immunohistochemically, the inflammatory infiltrate of the fat lobule consisted of CD68+ histiocytes and suppressor/cytotoxic T lymphocytes. In contrast, the lymphoid follicles in the septa and at the interface between septum and fat lobule were mainly composed of B lymphocytes.

LIMITATIONS

Only one biopsy was performed in each patient and, therefore, it was not possible to study the histopathologic evolution of the panniculitic process.

CONCLUSIONS

Localized panniculitis at the sites of subcutaneous injections of glatiramer acetate for treatment of multiple sclerosis seems to be a rare, but characteristic side effect of this therapy. The histopathologic pattern of these lesions consists of a mostly lobular panniculitis, with histiocytes and T lymphocytes in the fat lobule and thickened septa with scattered lymphoid follicles, which are mostly composed of B lymphocytes.

Detection of clonal rearrangement of T-cell receptor genes in the diagnosis of primary cutaneous CD30+lymphoproliferative disorders

BACKGROUND

Detection of clonality has been reported to be a helpful tool in the diagnosis of cutaneous lymphomas. Monoclonal rearrangement of T-cell receptor genes (TCR) was reported in fresh frozen tissue of lymphomatoid papulosis (LyP) and primary cutaneous anaplastic large-cell lymphoma (ALCL), but the diagnostic value of T-cell clonality in formalin-fixed, paraffin-embedded biopsies has so far not been assessed.

METHODS

Detection of clonal rearrangement of TCRgamma genes by highly sensitive polymerase chain reaction-based automated high-resolution fragment analysis (AHRFA) in archival LyP (n = 18) and ALCL (n = 17) tissue.

RESULTS

Detection of clonality differed significantly among the histologic forms of LyP as well as between LyP and ALCL with clonality found in none of the 10 biopsies of LyP type A and B, in 4/8 (50%) of the LyP type C specimens, and in 11/17 (65%) of ALCL cases.

CONCLUSIONS

T-cell clonality can only be found in a minority (four of 18; 22%) of archival LyP specimens, even when employing a highly sensitive detection method and is thus of limited diagnostic value. Final diagnosis of LyP has to be based mainly on clinical, histologic, and immunohistochemical findings rather than on results of clonality studies.

Primary Cutaneous Lymphoproliferative Disorders With Dual Lineage Rearrangement

We present a series of 15 cases of cutaneous lymphoma and pseudolymphoma with dual lineage rearrangement identified among approximately 1200 cases of cutaneous lymphoproliferative disorders assessed in our 4 institutions during the last 8 years in which the results of both T-cell receptor and immunoglobulin heavy chain rearrangement investigations were available. On the basis of the clinicopathologic information, the cases were retrospectively subdivided into 2 categories: (1) cases with definite features of cutaneous lymphoma or pseudolymphoma (n = 11) and (2) cases with unclassifiable disease (n = 4). The detection of dual genotype in the first group did not influence the final diagnosis; 7 cases represented cutaneous B-cell lymphomas, 3 pseudolymphomas, and 1 case lymphomatoid papulosis. The presence of monoclonal T-cell receptor-gene rearrangements in these cases may be explained either by monoclonal or oligoclonal expansion of exuberant T cells (or B cells in case of lymphomatoid papulosis) or by lineage infidelity. Three patients with unclassifiable disease had several clinical and histopathologic features in common. They were elderly, presented with solitary lesions, were in good general health and histopathologically demonstrated a dense multinodular infiltrate containing approximately an equal number of T and B cells and a high number of histiocytes forming granulomas, with prominent granulomatous features in 2 cases. B cells were either scattered with the infiltrate or formed collections vaguely resembling follicles; Reed-Sternberg-like cells were seen in 2 cases. B cells showed expression neither of immunoglobulin light chain. The T-cell component was represented mainly by small, well-differentiated lymphocytes or slightly pleomorphic cells, with some medium-sized convoluted cells. Epstein-Barr virus was not detected by polymerase chain reaction. The exact classification of these cases is unknown; they differ histopathologically from previously published cases of bigenotypic cutaneous lymphomas. They may merely represent a growth or reactive pattern, but, on the other hand, may be low-grade lymphomas. If so, they may be histopathologically related to cutaneous Hodgkin disease, T-cell/histiocyte-rich large B-cell lymphoma, or composite lymphomas. Further reports are needed to identify these lesions to clarify their nature and biologic potential.

Seborrheic keratosis with pseudorosettes and adamantinoid seborrheic keratosis: two new histopathologic variants

AIMS

Seborrheic keratoses are the most common benign cutaneous neoplasms in adult and middle-age patients. There are six distinctive histopathologic variants of seborrheic keratosis, namely, acanthotic or solid, reticulated or adenoid, hyperkeratotic or papillomatous, clonal or nested, irritated and inflamed.

METHODS

We report two additional histopathologic variants of seborrheic keratosis.

RESULTS

One lesion showed abundant intercellular mucin, closely resembling to adamantinoma, and therefore was named adamantinoid seborrheic keratosis. The other one exhibited a peculiar distribution of the basaloid keratinocytes, which were arranged radially around small central spaces, resulting in pseudorosette formation.

DISCUSSION

To our knowledge, these two histopathologic variants of seborrheic keratosis have been not previously described in the literature.