The T1796A mutation of the BRAF gene is absent in Spitz nevi

BACKGROUND

BRAF, a serine/threonine kinase, is a component of the retrovirus-associated sequence (RAS)-RAF-extracellular-regulated protein kinase (ERK)-MAP kinase signal transduction pathway mediating signals from RAS to ERK. The T1796A single point mutation in exon 15 of the BRAF gene has recently been reported in a high percentage of malignant melanomas and benign melanocytic lesions such as congenital nevi, compound nevi, intradermal nevi and dysplastic nevi. The T1796A mutation has been shown to promote cell proliferation.

METHODS

We screened 21 Spitz nevi and six spitzoid malignant melanomas for the presence of the T1796A BRAF mutation.

RESULTS

The T1796A BRAF mutation could not be detected in any of the 21 Spitz nevi but was present in two of the six spitzoid malignant melanomas.

CONCLUSIONS

Our results, in conjunction with data from a previous investigation, suggest that the melanocytic proliferation of Spitz nevi might be induced by components of the RAS-RAF-ERK-MAP kinase pathway different from BRAF, possibly combined with other genetic aberrations. The lack of the T1796A BRAF mutation might be of practical importance in distinguishing Spitz nevi from other melanocytic lesions simulating Spitz nevi as a part of a future complex diagnostic assay.

Pityriasis lichenoides: a cytotoxic T-cell-mediated skin disorder. Evidence of human parvovirus B19 DNA in nine cases

BACKGROUND

Pityriasis lichenoides et varioliformis acuta (PLEVA) and pityriasis lichenoides chronica (PLC) probably represent the polar ends of the same pathologic process, i.e. pityriasis lichenoides (PL), with intermediate forms in between. Previous studies have demonstrated that the inflammatory infiltrate in PLEVA is composed of cytotoxic suppressor T cells, whereas in PLC the helper/inducer T-cell population drives the immunological answer. Furthermore, monoclonal rearrangement of the T-cell receptor-gamma (TCR-gamma) genes was repeatedly found both in PLEVA and PLC.

METHODS

Forty-one formalin-fixed, paraffin-embedded tissue specimens of 40 cases of PL were retrieved from the files of the authors. Immunophenotyping for cytotoxic granular proteins (Tia-1/GMP-17 and Granzyme B) and T-cell-related antigens (n = 41), TCR-gamma chain gene analysis (n = 30) and molecular investigations for parvovirus B19 (PVB19) DNA (n = 30) were performed.

RESULTS

Overlapping immunophenotypes were observed in PLEVA and PLC. The dermal and epidermal T cells predominantly expressed CD2, CD3, CD8, and Tia-1 with a variable positivity for CD45RA, CD45RO, and Granzyme B. A monoclonal rearrangement pattern of the TCR-gamma genes was detected in three cases (10%). PVB19 DNA was found in nine cases (30%). T-cell monoclonality in conjunction with genomic PVB19 DNA was present in one case.

CONCLUSIONS

Our results demonstrate that PL is a skin disorder mediated by the effector cytotoxic T-cell population. The identification of PVB19 DNA in nine cases may be interpreted ambiguously: PVB19 as a true pathogen or as an innocent bystander.

The anti-MAGE antibody B57 as a diagnostic marker in melanocytic lesions

The differentiation of melanoma from certain benign melanocytic lesions on histologic grounds alone may sometimes be difficult. The anti-MAGE antibody 57B was suggested to be a useful adjunct in differentiating melanoma from nevi. Our aim was to study MAGE immunoreactivity with B57 in benign melanocytic lesions that have not been investigated to this end so far. One hundred six benign melanocytic lesions were stained with the monoclonal antibody 57B. They included deep-penetrating nevus (n = 6), desmoplastic nevus (n = 9), halo nevus (n = 10), persistent melanocytic nevus (n = 12), common blue nevus (n = 17), cellular blue nevus (n = 8), cellular blue nevus with microalveolar pattern (n = 3), desmoplastic cellular blue nevus (n = 6), epithelioid blue nevus (n = 2), sclerotic blue nevus (n = 3), and clonal nevus (n = 30). Fifty-two lesions (49%) demonstrated various patterns of MAGE immunoreactivity, with clonal nevi and deep-penetrating nevi showing the most consistent staining. In conclusion, MAGE immunoreactivity detected by the monoclonal antibody 57B in formalin-fixed, paraffin-embedded tissue can be observed in benign melanocytic lesions, and therefore this antibody cannot be used in the differential diagnosis between melanoma and nevi.

Hobnail hemangiomas (targetoid hemosiderotic hemangiomas) are true lymphangiomas

BACKGROUND

Hobnail hemangioma (targetoid hemosiderotic hemangioma) is a small benign vascular tumor of the superficial and mid-dermis. In contrast to its well-characterized histology, it has been unclear whether this tumor arises from blood vessel endothelial cells (BECs) or lymphatic vessel endothelial cells (LECs).

METHODS

We analyzed 10 hobnail hemangiomas by immunohistochemistry, using the recently described lymphatic endothelial cell marker, D2-40. For comparison, CD31, CD34, and alpha-smooth muscle actin expression were studied in consecutive sections of the paraffin-embedded tissues.

RESULTS

In all analyzed vessels, D2-40 labeled exclusively LECs, whereas BECs were consistently negative. In contrast to capillary BECs, either neighboring the tumors or intermingled, neoplastic endothelial cells of all 10 hobnail hemangiomas were strongly labeled by D2-40.

CONCLUSIONS

The results suggest a lymphatic origin for hobnail hemangiomas. This view is further supported by the CD34 negativity of endothelial cells and the lack of actin-labeled pericytes in hobnail hemangiomas, both characteristic of lymphatic vessels. Moreover, our analysis revealed that microshunts between neoplastic lymphatic vascular channels and small blood vessels occur, explaining some features of hobnail hemangiomas, such as aneurysmatic microstructures, erythrocytes within and beneath neoplastic vascular spaces, inflammatory changes, scarring, and interstitial hemosiderin deposits.

Mutations of the BRAF gene in benign and malignant melanocytic lesions

A single-point mutation in exon 15 of the BRAF gene has recently been reported in a high percentage in cultured melanoma cells and in 6 of 9 primary melanomas examined. To evaluate the impact of the T1796A BRAF mutation, we screened primary melanomas, various types of nevi and lesions where a melanoma developed in an underlying nevus. We could detect the mutation in 28 of 97 (29%) melanomas and in 39 of 187 (21%) nevi, including blue nevi (0/20) and Spitz nevi (0/69), which did not carry the mutation. In melanomas with an underlying nevus, either the mutation was present in both the laser-microdissected nevus cells and the laser-microdissected melanoma cells (3/14) or both lesions were negative for the BRAF mutation except one case. In conclusion, mutations in exon 15 of the BRAF gene are nonspecific for progression of a nevus to a melanoma. Other so far unknown cofactors seem to be of importance.

Fallberichte

Nephrogenic fibrosing dermopathy (NFD) is a scleromyxoedema-like disease favoring the extremities and trunk. Histologically there is a cellular fibrosis throughout the entire dermis. NFD is associated with renal insufficiency and dialysis, although the pathogenesis has not been elucidated. A 71-year-old woman developed classical symptoms of NFD on both legs within a few weeks after initiation of hemodialysis and concomitant antibiotic treatment followed by presumed drug eruption.

[Squamous epithelial carcinomas of the face with neurotropic growth]

BACKGROUND AND OBJECTIVE

Invasion of squamous cell carcinoma of the head and neck into cutaneous nerves is rare and can easily be missed. Perineural outgrowth into cerebral nerves may result in severe pain or neurological disturbances. In addition, these carcinomas more often recur or metastasize and therefore are associated with a poor prognosis.

PATIENTS/METHODS

We report on two patients with squamous cell carcinoma of the dorsum of the nose and lower lip exhibiting neurotropic growth.

RESULTS

Histology showed pleomorphic keratinocytes growing deep into the subcutaneous tissue and bone, respectively. The presence of few pleomorphic keratinocytes could be only confirmed by immunohistochemistry, though indicated by a perineural lymphocytic infiltrate. In both patients, several re-excisions were necessary to achieve cure.

CONCLUSIONS

In neurotropic squamous cell carcinoma a consequent radical micrographic surgery as well as neurological and radiological investigations are mandatory. We also review the literature.

Haemorrhagic dermatomyofibroma (plaque-like dermal fibromatosis): clinicopathological and immunohistochemical analysis of three cases resembling plaque-stage Kaposi's sarcoma

AIMS

Dermatomyofibroma (plaque-like dermal fibromatosis) represents a distinct clinicopathological entity in the spectrum of cutaneous mesenchymal neoplasms showing a myofibroblastic line of differentiation. These benign neoplasms occur frequently, but not exclusively, in young women, and the shoulder girdle as well as the upper trunk are common locations. Histologically, dermatomyofibroma is characterized by a plaque-like proliferation of cytologically bland spindle-shaped tumour cells containing an ill-defined, pale eosinophilic cytoplasm and elongated, neuroid nuclei. Neoplastic cells are arranged in bundles and fascicles orientated parallel to the skin surface, adnexal structures are spared and elastic fibres are increased and fragmented. Immunohistochemically, tumour cells express vimentin and variably muscle actin and alpha-smooth muscle actin, but are negative for desmin, CD34, S100, and epithelial markers. The main differential diagnosis includes hypertrophic scar, dermatofibroma (fibrous histiocytoma), pilar leiomyoma, neurofibroma, adult myofibromatosis, extra-abdominal fibromatosis and plaque-stage dermatofibrosarcoma protuberans.

METHODS AND RESULTS

We report three cases of dermatofibroma arising in male patients aged 31, 36, and 47 years on the thigh, chest wall and back, respectively. All lesions were completely excised and no local recurrence has been reported. Histologically, the neoplasms showed classical features of dermatomyofibroma; however, in addition abundant extravasated erythrocytes, scattered inflammatory cells, numerous capillaries, and sieve- and slit-like spaces, features resembling plaque-stage Kaposi's sarcoma, were noted. In none of the cases did spindled tumour cells stain positively for CD34, and HHV8 was not detected by polymerase chain reaction.

CONCLUSIONS

The reported cases widen the clinicopathological spectrum of dermatomyofibroma and emphasize plaque-stage Kaposi's sarcoma as an additional differential diagnosis.

Cutaneous myoepithelial neoplasms: clinicopathologic and immunohistochemical study of 20 cases suggesting a continuous spectrum ranging from benign mixed tumor of the skin to cutaneous myoepithelioma and myoepithelial carcinoma

BACKGROUND

Myoepithelial neoplasms, both benign and malignant, are rare but well-established clinicopathologic entities in the salivary glands, the breast, and the lung. Despite similarities between cutaneous sweat glands and glandular structures in the above-mentioned organs as well as the presence of regular myoepithelial cells around cutaneous eccrine/apocrine glands, the concept of cutaneous myoepithelial neoplasms is still debatable and not commonly accepted.

METHODS

Twenty cutaneous myoepithelial neoplasms have been studied histologically and immunohistochemically.

RESULTS

Nine neoplasms showed features of benign mixed tumor of the skin (chondroid syringoma) (five females and four males, age range 19-65 years, all cases arose in the head and neck region). Two cases represented the eccrine and seven the apocrine subtype. Interestingly, in three cases of the apocrine subtype, solid areas composed predominantly of myoepithelial cells were detected; these neoplasms were designated as benign mixed tumors with prominent myoepithelial cells. Nine cutaneous neoplasms were composed of spindled, epithelioid, and plasmocytoid cells without ductal differentiation and immunohistochemically stained variably positive for vimentin, epithelial and myogenic markers, S-100 protein, calponin, and glial fibrillary acidic protein (four females and five males, age range 3-71 years, four cases arose in the head and neck region and one case each on the finger, the thigh, the lower leg, the foot, and the breast, respectively); these neoplasms were designated as cutaneous myoepitheliomas. Two morphologically malignant neoplasms with cytologic and immunohistochemical features of myoepithelial cells arose on the face of a 70-year-old female and a 79-year-old male patient; these neoplasms were designated as malignant cutaneous myoepitheliomas (cutaneous myoepithelial carcinomas).

CONCLUSIONS

The study suggests a continuous spectrum of cutaneous myoepithelial neoplasms ranging from benign mixed tumor of the skin to cutaneous myoepithelioma and cutaneous myoepithelial carcinoma. Further studies with extended follow-up information are necessary to establish prognostic factors.

Cutaneous involvement in multiple myeloma: a clinicopathologic, immunohistochemical, and cytogenetic study of 8 cases

BACKGROUND

Specific cutaneous involvement in patients with multiple myeloma (MM) is very uncommon. It usually occurs in late stages of MM as a reflection of increased tumor cell burden. We studied 8 patients with cutaneous involvement of MM without underlying bony lesions and reviewed the literature on this rare dermatologic manifestation.

DESIGN

We were particularly interested in the clinical course of patients with MM and cutaneous metastases, including survival once metastases were detected and the possible influence of various forms of therapy. Our goal was also to identify the immunoglobulin and the light-chain type in these cases, with emphasis on any possible association between a particular immunoglobulin class and cutaneous involvement, as well as the histopathologic, immunohistochemical, and cytogenetic features of the neoplastic plasma cells involving the skin.

SETTING

University department of dermatology, university hospital, and private practice.

PATIENTS

Medical records and biopsy specimens from 8 patients with MM and specific cutaneous lesions were reviewed.

RESULTS

Cutaneous lesions consisted of multiple erythematous or violaceous nodules or plaques with a wide anatomical distribution. Histopathologically, 2 different patterns were identified: nodular and diffuse interstitial. Neoplastic plasma cells showed atypical features, and in 1 case they displayed a spindle shape, giving a sarcomatoid appearance to the lesion. Immunohistochemical studies demonstrated that neoplastic plasma cells were strongly positive for CD79a, CD138, and epithelial membrane antigen, and variably positive for VS38c and CD43. In each case the immunoglobulin profile and the light-chain type expression of the neoplastic cells were the same as those identified in the serum of the patients: 5 cases were IgA lambda; 2 cases were IgG kappa; and 1 case was IgA kappa. In cases 2, 3, and 4, polymerase chain reaction investigations revealed monoclonal rearrangement for IgH genes, whereas the investigations for human herpesvirus 8 and Epstein-Barr virus yielded negative results. Fluorescent in situ hybridization investigations in these 3 cases demonstrated that the cutaneous neoplastic plasma cells showed the deletion of the rb-1 (retinoblastoma) gene. Despite aggressive chemotherapy, all 8 patients died a few months after the development of cutaneous involvement.

CONCLUSIONS

In our series, there was a perfect correlation of immunoglobulin and light-chain type between the serum electrophoresis and the cutaneous plasma cells. Patients with MM showed a short survival once cutaneous metastases appeared independently of the therapy. The deletion the rb-1 gene may provide prognostically relevant information to identify a high-risk subset of patients with MM.

Trichogerminoma: a rare cutaneous adnexal tumor with differentiation toward the hair germ epithelium

In 1992, Sau and colleagues described 14 cases of a rare cutaneous adnexal tumor with differentiation toward the hair germ epithelium. All cases in their study displayed a unique constellation of histological features which allowed the authors to consider the neoplasm to be a distinct entity and to designate it as 'trichogerminoma' (TG). We present a case of an adnexal tumor identical to that described as TG and report the immunophenotypical features of this neoplasm for the first time. A biopsy from a 41-year-old man revealed a well-demarcated epithelial tumor composed of multiple lobules located in the deep dermis without connection to the overlying epidermis and surrounded by a fibrous pseudocapsule. The tumorous lobules were composed of uniform basophilic cells with vesicular nuclei, dispersed chromatin and prominent nucleoli showing no prominent peripheral palisading. Some of the lobules had the appearance of densely packed 'cell balls' with peripheral condensation of the tumor cells. The stroma showed a moderate number of fibroblasts and mast cells. Reticulum staining revealed fine reticulum fibers surrounding the tumor aggregates with accentuation of the 'cell balls'. Immunohistochemically, the tumor cells expressed AE1/AE3, CK5/8, CK5/6, CAM5.2 and stained negatively for CK20, CK7, calretinin, Lu-5 and Thomsen- Friedensreich antigen. There was no increase in the numbers of CK20-positive Merkel cells in the epidermis overlying the tumor; however, a few Merkel cells were scattered in some tumor lobules. In addition, we stained 6 trichoblastomas (TBs) and found a particular pattern of calretinin expression in this tumor which was not observed in our case of TG. We conclude that pathological features allow the delineation of TG as a distinct adnexal neoplasm. Histological differential diagnosis includes basal-cell carcinoma (pilar type), large nodular TB, trichoblastic fibroma, trichoepithelioma, tricholemmoma, pilomatricoma and matrical carcinoma.

Loss of expression of tuberin and hamartin in tuberous sclerosis complex-associated but not in sporadic angiofibromas

BACKGROUND

Angiofibromas occur sporadically, and they develop in most patients with tuberous sclerosis complex (TSC), which is associated with alterations of the tumor suppressor genes TSC1 or TSC2. Loss of tuberin, the protein product of TSC2, has been shown in the interstitial fibroblast compartment of TSC-associated angiofibromas. It is unclear whether there is also a loss of hamartin, the product of TSC1 in TSC-associated and sporadic angiofibromas.

METHODS

The expression of hamartin and tuberin was analyzed by immunohistochemistry in 59 TSC-associated and 12 sporadic angiofibromas using affinity-purified antibodies.

RESULTS

Loss of expression of both tuberin and hamartin was detected in 14 angiofibromas, loss of only tuberin in three, and loss of only hamartin in four TSC-associated angiofibromas; but there was no loss in the sporadic angiofibromas. Only the interstitial cells, but not the vascular cells, showed a loss of expression of tuberin or hamartin.

CONCLUSIONS

Loss of tuberin or hamartin occurred in a minority of the TSC-linked angiofibromas, but not in the sporadic angiofibromas. The absence of both tuberin and hamartin in some of the tumors suggests that the stability of tuberin and hamartin, which are believed to form an active complex in vivo, is negatively affected by the absence of either of the partners.

Interstitial granulomatous dermatitis with histiocytic pseudorosettes: a new histopathologic pattern in cutaneous borreliosis. Detection of Borrelia burgdorferi DNA sequences by a highly sensitive PCR-ELISA

BACKGROUND

The cutaneous manifestations of Borrelia burgdorferi infection include an early phase of erythema chronicum migrans and a late stage of acrodermatitis chronica atrophicans lesions.

OBJECTIVE

We describe 11 patients with peculiar cutaneous manifestations and distinctive histopathologic findings as the result of B burgdorferi infection.

METHODS

Eleven patients with B burgdorferi detected by polymerase chain reaction or polymerase chain reaction enzyme-linked immunosorbent assay in their cutaneous lesions were included in this study. We analyzed clinical data and histopathologic findings in all patients. The inflammatory infiltrate was also immunohistochemically investigated.

RESULTS

Most patients showed a peculiar clinical setting of morphea, and a few cases presented the characteristic appearance of erythema chronicum migrans instead of acrodermatitis chronica atrophicans, as would be expected in a late phase of B burgdorferi infection. The histopathologic findings were similar in all cases and consisted of an interstitial inflammatory infiltrate mostly composed of histiocytes dispersed among the collagen bundles of the dermis and focal areas of small pseudorosette formation, characterized by small histiocytes radially disposed around thick collagen bundles. In some cases there were also a few plasma cells intermingled with the histiocytes.

CONCLUSION

Cutaneous lesions with clinical appearance similar to that of morphea and histopathologic features closely resembling those of the interstitial type of granuloma annular may be seen in intermediate-stage cutaneous lesions of B burgdorferi infection. These clinical and histopathologic findings represent a constellation of findings that have not been previously characterized as a cutaneous manifestation of B burgdorferi infection.

Cytotoxic mycosis fungoides evolving from pityriasis lichenoides chronica in a seventeen-year-old girl. Report of a case

Pityriasis lichenoides chronica and its acute form, pityriasis lichenoides et varioliformis acuta, are skin diseases of unknown origin, that probably represent a hypersensitivity reaction to an infective agent. Pityriasis lichenoides is often a benign disorder but, because of the presence of a clonal T cell population detected both in the chronic and acute forms, some authors have suggested that it may belong to the group of primary cutaneous T cell lymphomas. Although various studies have clearly documented no significant association between pityriasis lichenoides and malignant lymphomas, cases of long-standing pityriasis lichenoides evolving into mycosis fungoides have been described. Herein we report the case of a girl suffering from pityriasis lichenoides since the age of 11 years, subsequently developing a CD45RO+, CD8+, TIA-1+ mycosis fungoides.

[Diffuse dermal angiomatosis]

Diffuse dermal angiomatosis (DDA) is a benign, acquired vascular proliferation characterized by painful, poorly circumscribed, livid-erythematous plaques with frequent central ulceration. The clinical features are reminiscent of reactive angioendotheliomatosis or embolia cutis medicamentosa. Histologically, a dense diffuse network of regular capillary vessels throughout the dermis is seen. Endothelial atypia, atypical mitoses or signs of vasculitis are missing. A 43-year-old woman developed a bizarre brownish-livid rapidly growing lesion of DDA 8 centimeters above a surgical scar, shortly after removal of 20 kilograms of fatty tissue from the lower abdominal wall. DDA regressed spontaneously within 12 weeks, and has not recurred over 4 years of follow-up.

Acquired elastotic hemangioma: A clinicopathologic variant of hemangioma

BACKGROUND

In recent years, many new cutaneous vascular proliferations have been described. This is partly due to the current epidemic of AIDS, which has forced dermatopathologists to establish the diagnosis of the earliest patch-stage lesions of AIDS-related Kaposi's sarcoma and some of the recently described cutaneous vascular proliferations that may histopathologically mimic lesions of early Kaposi's sarcoma.

OBJECTIVE

This article reports the clinical, histopathologic, and immunohistochemical findings in 6 cases of a clinicopathologic variant of cutaneous hemangioma, which we have named acquired elastotic hemangioma.

METHODS

Six cases of acquired elastotic hemangioma were studied from clinical, histopathologic, and immunohistochemical standpoints. The histopathologic differential diagnosis with other similar cutaneous vascular proliferations is discussed.

RESULTS

Acquired elastotic hemangioma appears on the sun-damaged skin of the dorsal aspect of the forearms or on the lateral aspects of the neck of middle-aged or elderly women. Clinically, lesions present as solitary erythematous plaques with variable morphology and in only some cases have a clearly angiomatous appearance. On histopathologic examination, acquired elastotic hemangioma is characterized by a band-like proliferation of capillary blood vessels involving the superficial dermis and arranged horizontally parallel to the epidermis.

CONCLUSION

Acquired elastotic hemangioma is a distinctive clinicopathologic variant of hemangioma that should be differentiated from other cutaneous vascular proliferations. On histopathologic examination, it is characterized by capillary proliferation involving the dermis.

CD34-positive glomus tumor: clinicopathologic and immunohistochemical analysis of six cases with myxoid stromal changes

BACKGROUND

Glomus tumors are benign, mainly superficially located perivascular neoplasms, composed of cytologically characteristic neoplastic cells staining immunohistochemically positive for vimentin and muscle actin, closely associated with often branching blood vessels.

METHODS

Six cases of glomus tumor were analysed histologically and immunohistochemically.

RESULTS

We report six cases of glomus tumor (three solid glomus tumors, two glomangiomas, one glomangiomyoma) arising on the fingers of adult patients (five female and one male patient; age range 35-65 years) that showed prominent myxoid stromal changes and immunohistochemically a coexpression of alpha-smooth muscle actin and CD34 by neoplastic cells.

CONCLUSIONS

Neoplastic cells in glomus tumor may show a coexpression of alpha-smooth muscle actin and CD34, an important finding regarding the differential diagnosis of these lesions and the relationship of perivascular neoplasms.

Circumscribed palmar or plantar hypokeratosis: a distinctive epidermal malformation of the palms or soles

BACKGROUND

Epidermal malformations of the skin include a group of heterogeneous developmental defects that result from errors in morphogenesis of the epidermis during intrauterine life.

OBJECTIVE

The purpose of this study was to report the clinical and histopathologic features of a distinctive epidermal malformation involving the skin of the palms or soles.

METHODS

Ten patients were included in this study. All of them showed the same clinical features that consisted of a solitary circumscribed and circular area of erythematous depressed skin on the palm or on the sole. Diagnosis was confirmed by histopathologic study.

RESULTS

All patients were middle aged or elderly. Nine patients were women and one was a man. The lesions showed predilection for the skin of the thenar and hypothenar regions of the palm or the medial side of the sole. Histopathologic study demonstrated a depression of the epidermis, with a sharp stair between normal and involved skin. The epidermis covering the depression showed markedly thinner horny layer and a slightly diminished granular cell layer when compared with adjacent noninvolved skin. Keratinocytes of the squamous cell layer, granular cells, and corneocytes showed, otherwise, a normal appearance. Serial sections failed to demonstrate cornoid lamellation.

CONCLUSION

On the basis of the clinical and histopathologic findings in these 10 patients, we have named this malformation circumscribed palmar or plantar hypokeratosis. This lesion seems to be a distinctive entity that has not been previously described.

Pigmented mammary Paget disease and pigmented epidermotropic metastases from breast carcinoma

Pigmented mammary Paget disease is a rare clinicopathologic variant of mammary Paget disease. It has been described in female and male patients with intraductal mammary carcinoma extending to the epidermis of the nipple and areola through a lactiferous duct. Pigmented cutaneous metastases from breast carcinoma are uncommon variants of epidermotropic metastatic breast carcinoma. All these lesions may mimic malignant melanoma clinically and histopathologically. From a histopathologic point of view, involvement of the dermoepidermal junction by neoplastic cells of the mammary carcinoma seems to be a prerequisite for development of the clinical pigmentation. We report three examples of pigmented mammary Paget disease and six cases of pigmented epidermotropic metastases from breast carcinoma, which were studied from both the histopathologic and immunohistochemical points of view. Two cases of pigmented mammary Paget disease and all cases of pigmented epidermotropic metastatic breast carcinoma showed the proliferation of dendritic melanocytes arranged as solitary units along the dermoepidermal junction and intermingled with the neoplastic cells of the mammary carcinoma in the superficial dermis. In one case of pigmented mammary Paget disease, there was abundant melanin within the cytoplasm of the Paget cells, but an increased number of melanocytes could not be demonstrated. Local production of melanocytic chemotactic factor by neoplastic cells of the mammary carcinoma when they reach the dermoepidermal junction has been postulated as the cause of the melanocytic proliferation and clinical hyperpigmentation of these epidermotropic breast carcinomas. Another possibility is the phagocytosis or transfer of melanin from melanocytes to the intraepidermal neoplastic cells of the breast carcinoma. Pigmented mammary Paget disease and pigmented epidermotropic metastatic breast carcinoma should be differentiated from melanoma clinical and histopathologically.

Fascin expression in CD30-positive cutaneous lymphoproliferative disorders

BACKGROUND

CD30-positive cutaneous lymphoproliferative disorders (LPD) represent a spectrum of diseases ranging from low-grade (lymphomatoid papulosis; LyP) to high-grade (pleomorphic and anaplastic large-cell lymphoma; PTL, ALCL) with overlapping morphologic and immunophenotypic features. The common phenotypic hallmark is the expression of CD30-antigen by the tumor cells which morphologically resemble Reed-Sternberg cells. Although LyP is a non-fatal recurring disorder, it is associated with systemic lymphomas including Hodgkin's lymphoma (HL), mycosis fungoides (MF) and ALCL in 5-20% of the cases. Currently there is no marker to predict the development of systemic lymphomas in patients with LyP. Fascin, an actin bundling protein, has recently been shown to be a unique marker found in almost 100% of classical HL.

METHODS

Because of the association of LyP with HL, fascin expression was analyzed by immunohistochemistry in LyP (n = 45), cutaneous CD30+ ALCL (n = 17) and pleomorphic T-cell lymphoma (n = 9) (PTL) and LyP associated with systemic lymphomas (7 HL, 2 ALCL, 1 MF), with the intent to determine if fascin expression can predict disease progression.

RESULTS

Fascin was expressed by tumor cells in 11/45 (24%) cases of LyP, 11/17 (64%) cases of ALCL, 7/9 (77%) cases of PTL and 6/10 (60%) cases of LyP associated with systemic lymphomas. Fascin expression in LyP was significantly less frequent than in ALCL (p < 0.001) and also than in LyP associated with lymphomas (p < 0.05). There was no significant difference of fascin expression within the histological subtypes of LyP. We found no evidence of ALK expression nor of Epstein-Barr virus expression in any case either by in situ hybridization or immunohistochemistry in the LyP cases associated with HL.

CONCLUSIONS

This is the first study to demonstrate that fascin is expressed in cutaneous CD30+ LPD and that it is a candidate marker of disease progression in LyP.

Benign vascular proliferations in irradiated skin

Several types of cutaneous vascular proliferations have been described in areas of irradiated skin, including both benign lesions, such as benign lymphangiomatous papules, atypical vascular lesions, or benign lymphangioendothelioma, and malignant neoplasms such as high-grade angiosarcomas. This report describes the clinicopathologic features of 15 cases of different types of benign cutaneous vascular proliferations arisen within irradiated skin. All patients were female ranging in age from 33 to 72 years, and they had received postoperative external radiotherapy for treatment of breast carcinoma (14 cases) or ovarian carcinoma (one case). In those cases in which the latency interval period between radiotherapy and the development of the vascular lesion was known from the clinical records, the latency interval period elapsed between radiotherapy and diagnosis of the vascular lesion ranged from 3 to 20 years. The most common clinical presentation of the cutaneous lesions consisted of papules, small vesicles, or erythematous plaques on the irradiated field. Histopathologically, most lesions consisted of irregular dilated vascular spaces, with a branching and anastomosing pattern, thin walls, and lymphatic appearance involving the superficial dermis. A discontinuous single layer of endothelial cells with flattened nuclei lined these vascular channels, and numerous small stromal papillary formations also lined by endothelial cells projected into the lumina of the dilated lymphatic vessels. These cases were classified as benign lymphangiomatous papules or plaques. Two cases showed different histopathologic findings because they consisted of poorly circumscribed and focally infiltrating irregular jagged vascular spaces involving the entire dermis and lined by inconspicuous endothelial cells. In some areas these irregular slit-like vascular spaces dissected collagen bundles of the dermis. These cases were classified as atypical vascular proliferations mimicking benign lymphangioendothelioma or patch-stage Kaposi's sarcoma. All cases showed similar immunohistochemical findings and the endothelial cells lining the vascular spaces expressed immunoreactivity for CD31, but they stained only focally positive for CD34 or were negative for this marker. Immunohistochemical investigations for alpha-smooth muscle actin failed to demonstrate a complete peripheral ring of actin-positive pericytes in most of the neoformed vascular structures. This immunohistochemical profile also supported the lymphatic nature of these vascular proliferations developed in irradiated skin. Although some of these lesions may mimic histopathologically patch-stage Kaposi's sarcoma or well-differentiated angiosarcoma, the follow-up of the patients of this series demonstrated that the vascular proliferations arisen in irradiated skin invariably showed a benign biologic behavior.

[Tumors of the lymphatic vessel of the skin and soft tissue]

Tumours of lymphatic vessels comprise only a small group in the heterogeneous spectrum of vascular neoplasms of skin and soft tissues. However, this discrepancy between haemangiomas/angiosarcomas and lymphangiomas/lymphangiosarcomas probably represents the present inability to reliably differentiate between lymphatic and capillary vascular endothelium. Histologically, neoplastic lymphatic vessels tend to be lined by endothelial cells with plumper and more prominent, matchstick-like nuclei (in contrast to vascular spaces in haemangiomas that are lined by flat or epithelioid endothelial cells), often show variations in the thickness of the vessel walls and are not completely surrounded by actin-positive (myo)pericytes. Endothelial cells in lymphatic neoplasms tend to be negative for CD34 or stain only focally positive for this marker and an expression of lymphatic markers as vascular endothelial growth factor-C receptor (VEGRF-3), podoplanin and M2A oncofetal antigen has been reported most recently. In addition to "traditional" lymphatic neoplasms including lymphangioma circumscriptum, cavernous lymphangioma/cystic hygroma, benign lymphangioendothelioma, lymphangiomatosis and the rare lymphangiosarcoma, histological and immunohistochemical features of a group of vascular neoplasms with a hobnail cytomorphology (hobnail haemangioma, retiform haemangioendothelioma, papillary intralymphatic angioendothelioma, benign lymphangiomatous papule following radiotherapy) suggest that these lesions also belong to the spectrum of tumours of lymphatic vessels.

Congenital giant melanocytic nevus with pigmented epithelioid cells: a variant of epithelioid blue nevus

Epithelioid-cell blue nevus is an unusual cytologic variant of blue nevus that has been recently described mostly in patients with Carney complex, although the lesion may also appear in patients with no evidence of Carney complex. This variant of blue nevus is composed of melanin laden large polygonal epithelioid melanocytes situated within the dermis. The neoplastic cells show no maturation with progressive descent and, in contrast with the usual stromal changes in blue nevi, epithelioid-cell blue nevus exhibits no dermal fibrosis. This report describes a congenital giant melanocytic nevus with pigmented epithelioid cells located on the back of a 2-year-old male. The lesion was present at birth and the patient had no evidence of Carney complex. Histopathologically, the lesion consisted of a large and entirely intradermal melanocytic nevus composed of heavily pigmented epithelioid melanocytes involving the full-thickness of dermis, but extending also to the subcutaneous fat and underlying soft tissues. Immunohistochemically, epithelioid neoplastic melanocytes expressed immunoreactivity for S-100 protein, HMB-45, Melan-A, NK1C3, and microphthalmia transcription factor (MiTF) antibodies. MIB-1 cellular proliferation marker was expressed in the nuclei of only a few scattered epithelioid melanocytes. This report demonstrates that epithelioid-cell blue nevus is a distinctive histopathologic variant of blue nevus that may also appear as a giant congenital melanocytic nevus.