Intraepidermal pilar epithelioma: a new dermatopathologic interpretation of a skin tumor

An intraepidermally developed epithelial cell tumor, forming multiple nests, was examined to identify its cytologic characteristics. Histochemically, the tumor cells contained neither glycogen nor lipid substance. By N-(7-dimethylamino-3-methyl-4-coumarinyl)maleimide staining, the cytoplasm of the tumor cells in the periphery of each nest was rich in SH groups but not in SS linkages, whereas centrally located homogeneous tumor cells contained SS diffusely but no SH. The tumor cells showed no activity of phosphorylase and a weak activity of succinic dehydrogenase. Immunohistochemically, antihair keratin monoclonal antibodies specific for hair cells decorated the tumor cells, but carcinoembryonic antigen staining showed no positivity. Ultrastructurally, the tumor cells underwent a keratinization forming a fingerprint pattern of keratin filaments; however, membrane-coating granules and marginal bands were not formed. These intraepidermal tumor cells may have cytologic natures similar to those of hair cortical cells. The term intraepidermal pilar epithelioma is proposed as a diagnosis for this tumor.

Cutaneous inverted papillomas in dogs

Inverted papillomas of the skin occurred in five dogs. Lesions were 1-2 cm, circumscribed, flask-like structures below the level of the surrounding normal skin. Walls of the structures consisted of hyperplastic epidermis, forming thin papillary projections on thin fibrovascular stalks. Cells in the stratum granulosum had clear cytoplasm, numerous keratohyalin-like granules of various sizes, and poorly defined intranuclear inclusions. These cells stained positively for papillomavirus group-specific antigens by both the peroxidase-antiperoxidase and avidin-biotin methods. Virions with a mean diameter of 35.7 nm were present within nuclei in cells of the stratum granulosum when examined by electron microscopy. In situ DNA hybridization, using a canine oral papillomavirus probe, localized papillomavirus DNA in canine oral papillomas, but not in canine cutaneous squamous or inverted papillomas, suggesting that a different papillomavirus type was present in the latter lesions. Although these lesions resembled intracutaneous cornifying epitheliomas (keratoacanthomas), they appear to be a distinct lesion, probably with a different etiology.

[The combination of atrial myxoma and multiple skin myxomas: a characteristic symptom complex?]

In 1980, a then 7-year-old boy from Yugoslavia had an atrial myxoma removed. Since then there have been no abnormal cardiac signs or symptoms. Between 1982 and 1986 five cutaneous myxomas in the trunk region were removed. None of the tumours had histological signs of malignancy. These observations can be fitted into the symptom complex (described in 1985 by Carney et al.) of cardiac myxoma, cutaneous myxoma, changes in skin pigmentation, and abnormal endocrine functions--although not all signs need be present together. A disposition towards the development of myxomatous tumours is to be assumed in these patients. One should, therefore, always suspect an occult cardiac myxoma in the presence of multiple cutaneous myxomas. Appropriate diagnostic measures need to be taken before the typical and sometimes lethal consequences of a cardiac myxoma have occurred.

Naevus fusco-caeruleus zygomaticus

One hundred and ten cases of an unusual type of naevus, which we have called naevus fusco-caeruleus zygomaticus were studied. The naevus presents as a bilateral speckled discolouration of the skin of the face principally in the zygomatic region. The condition usually does not become apparent until the second decade of life, and is much commoner in females. No association with any other abnormalities was found. Light and electron microscopy of the speckles showed the presence of dermal melanocytes mostly in the upper dermis. A survey was also carried out to determine the prevalence of this naevus in the general population.

Angiosarcomas in chronically lymphedematous extremities. Two cases of Stewart-Treves syndrome

Two cases of Stewart-Treves syndrome are presented. The first case consists of an angiosarcoma developing in long-standing postmastectomy lymphedema. The second case has an unusual localization on the lower extremity. The results of immunohistochemical stainings with Factor VIII-related antigen, UEA-1 lectin, and laminin support the assumption that Stewart-Treves syndrome is a hemangioendotheliosarcoma.

Trabecular (Merkel cell) carcinoma arising in the wall of an epidermal cyst

A trabecular (Merkel cell) carcinoma arising in the wall of an epidermal cyst in a 58-year-old white male metastasized, 17 months after local excision, to an inguinal lymph node. Ultrastructural studies showed polygonal tumor cells with typical dense-core granules. Although squamous-cell carcinoma and other malignant neoplasms have been reported rarely to have arisen in epidermal cysts, a literature search failed to find a precedent for the present case.

Hair matrix differentiation. Occurrence in lesions other than pilomatricoma

The formation of structures resembling hair matrices is the least common form of follicular differentiation and only occurs with any frequency in pilomatricoma. Rarely, follicular cysts and both benign and malignant adnexal tumors can show areas of pilomatricoma-like change, or hair matrix differentiation. Examples of focal hair matrix differentiation in a follicular cyst, a cutaneous mixed tumor, and an adnexal carcinoma are presented. Each of these cases also demonstrates the presence of limited differentiation toward structures of the inner root sheath.

Kaposi's sarcoma in AIDS. Multicentric angioneoplasia in early skin lesions

Light-microscopic, immunohistochemical, and ultrastructural studies were performed on biopsy material from 15 young homosexual men with AIDS-associated mucocutaneous Kaposi's sarcoma; 19 Kaposi's sarcoma lesions in different developmental stages were investigated. These lesions showed multicentrically arising and proliferating vascular endothelia forming thick-walled and thin-walled capillaries and larger vessels, as well as spindle-shaped cells forming fascicles and bundles around them. Different amounts and organization of these two major cellular components were found in all stages of evolution of Kaposi's sarcoma lesions. Immunohistochemical and electron-microscopic techniques suggested that the spindle-shaped cells were of pericyte origin in different stages of maturation or, more rarely, lymphatic endotheliocytes. The skin lesions of AIDS-associated Kaposi's sarcoma occurred as a result of multicentric angioneoplasia of rather slow progression, together with the proliferation of pericyte-like mesenchymal cells, possibly representing a stromal reaction to the vascular proliferation. Both blood and lymphatic vessels seemed involved in this process. In early stages, scattered lymphocytic infiltration was an additional feature. Mitotic figures and cytologic atypia were not seen more frequently in early AIDS-associated Kaposi's sarcoma than in proliferating granulation tissue.

Generalized hair follicle hamartoma: the third case report in association with myasthenia gravis

A 29-year-old woman, referred because of the development of diffuse papules and plaques on the face and progressive hair loss, was found to have generalized hair follicle hamartoma, a very rare condition previously described in only two female patients. All three patients also suffered from myasthenia gravis. The histological appearance of both the involved and uninvolved skin was similar to trichoepithelioma.

The keratotic tumors of Cowden's disease: an electronmicroscopic study

Cowden's disease is characterized by multiple hamartomas of the skin, breast, thyroid, and gastrointestinal tract. In the past, a viral hypothesis for the keratotic lesions of the skin has led to much controversy. The present study describes the results of a detailed fine structural analysis of 10 hyperkeratotic extremity lesions and 2 keratotic lesions from the face of a patient with Cowden's disease. Increases in the keratinocyte population were primarily confined to the basal and suprabasal regions. Differentiation products characteristic of keratinization were normal in both quantity and appearance. Nuclear remnants and numerous lipid droplets, markers of abnormal keratinization, were noted within horny cells. However, viral particles and/or virus-like particles were not observed in keratinocytes. Melanocytes and Langerhans cells were numerous. The latter contained membrane-bound pigment vacuoles in addition to the characteristic Birbeck granules. These unusual Langerhans cells were observed in the dermis as well as the epidermis. A large number of fully granulated "resting" mast cells was uniformly distributed throughout the dermis, associated with a prominent cellular infiltrate. Our observations do not support the concept of a viral etiology for these tumors.

Recurrent and metastatic cutaneous neuroendocrine (Merkel cell) carcinoma mimicking angiosarcoma

An elderly man presented with bright red-to-purple confluent nodules and plaques of the scalp that appeared clinically consistent with angiosarcoma. He had undergone surgical removal of a similar lesion from his left temple seven months before this presentation. Although routine histologic examination was not sufficient for diagnosis, Merkel cell carcinoma was diagnosed by immunohistochemical studies and electron microscopy. In addition, oat cell carcinoma of the lung was excluded with a computed tomographic scan of his chest. With chemotherapy, the recurrent and metastatic lesions of Merkel cell carcinoma completely resolved, rapidly recurred, and resolved a second time with chemotherapy. Eight months following the fourth course of chemotherapy, the patient again developed widespread cutaneous lesions. He committed suicide within one month of this last recurrence. An autopsy revealed no primary tumor other than of the skin.

Histogenesis of Kaposi's sarcoma associated with AIDS: a histologic, immunohistochemical and enzyme histochemical study

Twenty-one cases (25 biopsies including 9 frozen biopsies) of Kaposi's sarcoma associated with the acquired immune deficiency syndrome (AIDS) were examined immunohistochemically, lectin-histochemically, and enzyme histochemically to ascertain the histogenesis of the lesion. The Kaposi's sarcomas were histologically subtyped according to a modified Schmid's classification (granulation tissue-like-, angiosarcoma-like- and spindle cell type). In almost all lesions, many atypical vasoforming cells and at least some spindle cells without definite evidence of vasoformation by conventional microscopy were positive for factor VIII-related antigen, BMA 120 (a new monoclonal antibody to an endothelial cell-specific antigen), Ulex europaeus I (UEA-I), alkaline phosphatase and ATPase. Linear reaction products for BMA 120 and UEA-I, suggesting the luminal surface of immature vascular channels, were sometimes recognized in the positive spindle cells. Electron micrographs confirmed endothelial characteristics, such as irregular and fragmented but distinct basal lamina and numerous pinocytotic vesicles, in both the UEA-I- and ATPase-positive spindle cells. Among spindle cells negative for the endothelial markers, there were many macrophages as a stromal reaction to tumor tissue, identified by monoclonal antibodies to macrophages (KiM 6, 7, 8 and EBM 11), acid phosphatase and alpha-naphthyl acetate esterase. The results of the immuno- and enzyme histochemical investigations did not correlate with the different histologic types of Kaposi's sarcoma. However, our results strongly suggest that tumor cells of Kaposi's sarcoma are derived from vascular endothelial cells rather than lymphatic endothelium.

A case of multiple piloleiomyoma associated with submucosal tumor of the stomach

A patient with disseminated type multiple piloleiomyoma is reported. He showed multiple painful intradermal nodules on the neck, the back, the chest and the back of the left hand. He had a submucosal tumor of the stomach, which was thought to be a leiomyoma. Multiple piloleiomyoma with other leiomyoma except for uterine myoma is unknown and very rare.

Histogenesis of subcutaneous malignant tumors resulting from nickel subsulfide implantation

Tumors are described which have been produced by subcutaneous (s.c.) implantation of nickel subsulfide (Ni3S2) in 00 gelatin capsules in the left axillary region of Fischer 344 rats. This is in contradistinction to previous accounts where intramuscular (i.m.) or, in a few cases, subcapsular testicular implantation sites have been used. The advantages of the s.c. route are discussed, including the removal of the difficulties of distinguishing degenerating and regenerating striated muscle cells from tumor cells. The s.c. induced tumors were transplanted as far as the F6 generation, in some cases. Cells from tumor transplanted as far as the F3 generation were grown in tissue culture and then reimplanted s.c. Cytology of the tumors remained remarkably constant in all tumors, even after serial transplants and culture. A characteristic storiform pattern, with two major cell types -myofibroblasts and histiocyte-like cells, was seen. The question of pluripotential cell origin is discussed. The striking similarity of appearance to human malignant fibrous histiocytoma is noted; however, in view of the somewhat controversial origin of the human tumor, the simple designation, "nickel-induced malignant tumor of pluripotential origin", is preferred. The use of this model with its demonstrated ability to reproduce characteristic appearances seems to be valuable for the study of soft tissue sarcomas.

Induction of melanogenesis in Schwann cell and perineural epithelium by 9,10-dimethyl-1,2-benzanthracene (DMBA) and 12-o-tetradecanoylphorbol-13-acetate (TPA) in BDF1 mice

Six-week-old female BDF1 mice were treated with a single topical application of DMBA followed by repeated application of TPA on the clipped dorsal skin. Several weeks after DMBA application, the intradermal melanocytes of perifollicular melanocytic network began to proliferate to form melanocytic tumors in all treated mice skin. Besides these changes, single membrane-bound melanosomes and premelanosomes were found in the cytoplasm of perineural epithelia and Schwann cells with mesaxons of the nerve bundles involved, and the melanogenic activity of the Schwann cell and the perineural epithelium of the dermal peripheral nerve bundle was discussed in terms of a common feature of neuro-ectodermal cells.

Morphological characterization of cellular and extracellular components of 7,12 dimethylbenz[a]anthracene induced melanoma tumours

Subcutaneous tumours were induced in castrated golden Syrian hamsters by 7,12 dimethylbenz[a]anthracene (DMBA), an agent known to produce papillomas and carcinomas. The morphological characteristics of the cellular and extracellular constituents of the chemically-induced tumours were indicative of melanoma. Tumours were induced by three injections of DMBA into the jugular vein over a 3 month period. Dermal tumour development within the dorsal integument and groin region ultimately projected into the epidermis and occurred during the 3 month period subsequent to the last DMBA injection. Suspect melanoma tumours were excised and processed for light microscopic (LM) and transmission electron microscopic (TEM) studies. Histochemical staining methods facilitated the characterization of the differentiated tumour components in this hamster melanoma model. The model presented could allow observations from initial melanoma transformation events through advanced stages of metastasis within a window of 7 months.

Acquired "tufted" angioma (progressive capillary hemangioma). A distinctive clinicopathologic entity related to lobular capillary hemangioma

Three young patients affected by intradermal and subcutaneous vascular proliferations are presented. The lesions were acquired and developed as solitary or multiple erythematous patches and plaques in the upper thorax, neck, and scalp. Light-microscopic examination revealed a deep-seated vascular growth with a distinctly lobular pattern. Ultrastructural and immunocytochemical studies demonstrated the cellular proliferation to be composed of endothelial and perithelial cells, the latter predominating. These cases are interpreted as examples of the vascular disorder described as progressive capillary hemangioma and acquired "tufted" angioma. We believe that it represents a distinctive clinicopathologic entity that is closely related histogenetically and perhaps pathogenetically to the entity recently renamed lobular capillary hemangioma.

Large congenital melanocytic nevus. Light and electron microscopic findings

The family of a 10-month-old black girl with a large periocular congenital melanocytic nevus (CMN) was given markedly differing advice from experienced physicians regarding how the lesion should be managed. The nevus was eventually removed surgically because of concern about the risk of malignant transformation and because of its cosmetic appearance. Histologically, the lesion was a dermal nevus, but extended deeply into subcutaneous tissue and had neuroid features. The ultrastructural characteristics of melanocytes varied according to the depth at which they resided, but cells did not differ basically from melanocytes found in smaller acquired nevi. Given the limited understanding of the biologic basis for malignant transformation, large size remains the most important risk factor in CMN.

Basal cell epithelioma with giant tumor cells: light and electron microscopic study

A case of basal cell epithelioma (BCE) with multiple large nuclei on the right buttock of a 69-year-old woman is reported, and the skin was studied by light and electron microscopy. This represented the only case (0.85%) of giant tumor cells with multiple nuclei among 117 patients with BCE. Ultrastructural studies revealed that giant tumor cells were not different from ordinary tumor cells of BCE, except for large convoluted nuclei. In the cytoplasms of giant tumor cells, we observed autophagic vacuoles which were derived from autophagocytosis. Scattered among the giant tumor cells, there were many degenerate tumor cells, some of which were phagocytized by giant tumor cells with multiple nuclei (referred to as macrophagocytosis). It is indicated that tumor cells have considerable phagocytic activities, and degrade the autophagic vacuoles or the degenerate tumor cells with the lysosomes. These findings suggest that the presence of the giant tumor cells with multiple nuclei does not indicate a increased malignant potential or anaplasia of the tumor, and that autophagocytosis or macrophagocytosis is a factor in initiating giant tumor cell formation.