Non-lymphoid lesions that may mimic cutaneous hematopoietic neoplasms histologically.

This review considers neoplastic lesions that originate in the skin, and which have the potential to imitate hematopoietic proliferations at a histological level. They include lymphoepithelioma-like carcinoma, Merkel cell carcinoma, benign lymphadenoma, pseudolymphomatous angiosarcoma, lymphadenoid dermatofibroma, lymphomatoid atypical fibroxanthoma, histiocytoid (epithelioid) hemangioma, and inflamed melanocytic lesions. The clinical and pathological features of those tumors are considered.

Atypical fibroxanthoma: a selective review.

The head and neck area has disproportionate number of cutaneous tumors given the surface area, as compared with the rest of the body. Many of the tumors are related to chronic actinic damage and the most common by far are squamous and basal cell carcinomas. Atypical fibroxanthoma refers to a group of usually indolent cutaneous tumors that occur in older adults and are characterized histologically by a population of fusiform, epithelioid, and pleomorphic cells, numerous cells in mitosis, and intracytoplasmic lipidization in some cells. Numerous histologic variants have been described, including a clear-cell, desmoplastic or keloidal, granular, angiomatoid, hemosiderotic, and myxoid, among others. These tumors have a mesenchymal immunophenotype. Some authors believe that atypical fibroxanthoma is a dedifferentiated variant of squamous cell carcinoma. We present a review of this particular neoplasm with special emphasis on the histomorphology, subtypes, immunophenotypic profile, and discussion of differential diagnosis.

Osteochondrolipoma: a subcutaneous lipoma with chondroid and bone differentiation of the chest wall.

Lipomas are the most common subtype of benign soft tissue neoplasms and can occur anywhere in the body. Differentiation into a diversity of mesenchymal elements, such as blood vessels, fibrous tissue or muscle, is a frequent event. However, the presence of bone or cartilage in these tumors is extraordinarily rare with very few cases reported in the head and neck area. We report a case of an 'osteochondrolipoma' of the chest wall, in a young individual, providing a rationale in support of this as a possible and distinctive histologic subtype of lipomas, as well as discussion in the differential diagnosis of this lesion.

Parathyroid hyperplasia of auto-transplanted tissue in forearm skin.

Currently, the treatment of choice for refractory tertiary hyperparathyroidism is a total parathyroidectomy with autotransplantation of the parathyroid tissue into the forearm. Recurrent hyperparathyroidism after autotransplantation requiring surgical excision of the autograft is uncommon. We describe a female patient with recurrent hyperplasia who underwent an excision of her parathyroid autograft. The excisional specimen was submitted to pathology with the only provided history of a 'left arm mass'. The lack of clinical history led to a preliminary impression of an adnexal neoplasm by the primary pathologist.

Lipodermatosclerosis: a clinicopathological study of 25 cases.

BACKGROUND: Lipodermatosclerosis is a chronic fibrosing process that involves both lower legs and classically affects Caucasian women in their 60s. OBJECTIVE: The objective is to define the histologic spectrum seen this condition. METHODS: A total of 25 cases were collected prospectively and all were stained with hematoxylin-eosin, von Kossa, and Verhoeff-van Gieson. RESULTS: Patient age ranged from 33 to 84 years (mean age 62.6 years). The female to male ratio was approximately 12 to 1. All lesions were present on the lower extremities, between the knee and ankle. Lesion duration ranged from 2 months to 2 years (mean 9.5 months). Clinically, the lesions were erythematous, tender, indurated plaques or nodules. The characteristic histologic findings were seen almost exclusively in the subcutaneous tissue, involving primarily the lobules but also the septa. Adipose changes included micropseudocyst and macropseudocyst formation, necrotic adipocytes, lipomembranous change, and lipogranulomas with xanthomatous macrophages. The lesions were largely devoid of dermal, septal, or lobular neutrophilic or lymphocytic inflammation. Medium vessel calcification was seen in 13 cases. The accumulation of basophilic elastic fibers located deep in the septa was present in all the cases. These fibers had a moth-eaten appearance and resembled pseudoxanthoma elasticum. In 21 of 25 cases, these fibers were positive with both the von Kossa and Verhoeff-van Gieson stains. LIMITATIONS: The cases in the series were not compared with age-, sex-, and location-matched biopsy specimens or biopsy specimens of other fibrosing conditions. CONCLUSION: This constellation of histologic changes is diagnostic of lipodermatosclerosis. The presence of pseudoxanthoma elasticum-like changes is a helpful, but not unequivocal, clue in this condition.

Sclerotic glomus tumor.

We report an unusual histopathological variant of a glomus tumor that arose in a peculiar topographic site, a sclerotic glomus tumor. Unlike conventional glomus tumors or glomangiomas that have a loose fibrous stroma with variable hyaline and myxoid changes, the case reported herein had a diffuse, hyalinized, sclerotic stroma. A further difference was that the majority of glomus tumors and glomangiomas occur in the subungual area, trunk, or extremities, whereas the present tumor occurred on the ear. Due to the peculiar histological features and location, other tumors were considered in the differential diagnosis to include Merkel cell carcinoma, primitive neuroectodermal tumor, and small cell melanoma. This article illustrates a unique variant of a glomus tumor, which to our knowledge has not been previously described.

Porokeratoma.

Cornoid lamellation is a specific disorder of epidermal maturation manifested by a vertical "column" of parakeratosis and is the hallmark of porokeratosis. The cornoid lamella is characterized by a ridgelike parakeratosis. We present 11 patients with solitary lesions of a distinct pattern of cornoid lamellation. The mean age at presentation clinically was 57 years; there were 9 men and 2 women. The duration of the lesions ranged from 3 months to 5 years (mean of 23 mo). All lesions were solitary, distributed mainly on the distal upper and lower limbs, and were clinically described as hyperkeratotic plaques or nodules; some were verrucous. Histologic examination showed a well-defined lesion characterized by acanthosis and verrucous hyperplasia with prominent multiple and confluent cornoid lamellae. No additional lesions were identified in any patient, with a mean follow-up duration of 34 months. No personal or family history of porokeratosis was elicited and no immunosuppressive conditions were noted. These lesions with multiple and confluent cornoid lamellae represent benign acanthomas with features of porokeratosis. As a solitary tumorlike lesion, it is akin to warty dyskeratoma and epidermolytic acanthoma, thus we have coined the term porokeratoma.

Psoriasiform keratosis.

Presented herein are 18 cases of erythematous, scaly papules or plaques with microscopic features of both seborrheic keratosis and psoriasis. There was, however, no known clinical diagnosis of psoriasis in any patient, neither at initial presentation nor on follow-up examination. Most lesions were solitary, present for 6-7 months, and identified on the upper or lower extremities. Other sites included the scalp, neck, shoulders, and back. Men were affected slightly more often than women. The mean age at diagnosis was 66.8 years. The most common diagnoses, clinically, were seborrheic keratosis, followed by basal cell carcinoma, Bowen's disease, actinic (solar) keratosis, and squamous cell carcinoma, among others. The lesions averaged less than a centimeter in diameter and were dome shaped, scaly, and yellow to gray-tan. Histologic examination revealed irregular verrucous epidermal acanthosis, with hyperkeratosis, parakeratosis, hypergranulosis, and intracorneal collections of neutrophils, often in alternating tiers. Vascular dilatation and lymphocytic chronic inflammation were present in the superficial dermis. Periodic acid-Schiff (PAS) stain for yeasts or dermatophytes was negative in all cases. There was no clinical evidence of disseminated psoriasis in any patient; the mean follow-up duration was 22.6 months. We have coined the term psoriasiform keratosis as a provisional appellation until the nature of these lesions is determined more definitively. It is unclear whether a psoriasiform keratosis is a rudimentary manifestation of psoriasis or a lesion sui generis.

Circumscribed acral hypokeratosis.

BACKGROUND: Circumscribed acral hypokeratosis (CAH) is an idiopathic condition that typically presents as an acquired, solitary, asymptomatic, well-defined, depressed, flat-based deformity, with a slightly raised border on the palm or, rarely, the sole. Histologically, the lesional epidermis is depressed with a characteristic, abrupt, hyperkeratotic, slightly-raised ridge at the transition from normal skin. OBJECTIVE: We sought to present 3 additional cases of CAH. METHODS: A review of 3 cases of CAH was performed. Liquid phase polymerase chain reaction (PCR) was conducted to evaluate for human papillomavirus (HPV). RESULTS: Three cases of CAH were reviewed. One patient had a history of a burn at the site prior to developing the disorder while another patient, as a child, had a history of verruca plantaris in the same location. Lesions were solitary, involving the palm or sole, in 2 cases and in one case they were multiple involving both the palms and the soles. HPV testing detected HPV type 6 in the lesion of one patient who previously was treated for warts in the same location. Topical fluorouracil, calcipotriol ointment under occlusion, and clobetasol ointment under occlusion were unsuccessful in one patient. LIMITATIONS: In case 2, we were pathology consultants and unable to evaluate the clinical appearance of the lesion. CONCLUSIONS: CAH may involve palms and/or soles. Lesions may be solitary or multiple, and vary widely in size. We believe that CAH most likely represents a reaction pattern developing in response to various stimuli, including trauma, HPV, or both.

Granular cell atypical fibroxanthoma.

We report on two patients with granular cell atypical fibroxanthoma. Both neoplasms were solitary, light-tan, dome-shaped papules on sun-exposed areas of the head in two elderly white men. Microscopically, these neoplasms showed a dermal proliferation of pleomorphic granular cells with irregular hyperchromatic nuclei, multinucleated cells, and scattered mitoses. Immunohistochemical stains were positive for CD68 and vimentin and negative for Melan-A or human melanoma black (HMB)-45, S-100 protein, pancytokeratin, and actin, consistent with atypical fibroxanthoma. The differential diagnosis of granular cells in neoplasms containing cytological pleomorphism is challenging in view of the many different neoplasms that may present with granular cytoplasm. These include the conventional granular cell tumor and its malignant form, leiomyoma, leiomyosarcoma, dermatofibroma, dermatofibrosarcoma protuberans, and angiosarcoma.

Vascular tumors of the skin: a selective review.

Cutaneous vascular proliferations are a vast and complex spectrum. Many appear as hamartomas in infancy; others are acquired neoplasms. Some vascular proliferations are hyperplastic in nature, although they mimic hemangiomas, i.e., neoplasms. The vast majority of the vascular lesions are hemangiomas. Between the hemangiomas and frankly angiosarcomas, there is a group of neoplasms that are angiosarcomas, albeit ones of low grade histologically and, probably, biologically. The term "hemangioendothelioma" has been created to encompass these neoplasms. Vascular proliferations are, fundamentally, composed of endothelial cells. Some hemangiomas, however, contain also abundant pericytic, smooth muscle, or interstitial components, or a combination of them. These heterogeneous cellular components are present usually in hemangiomas. Some of the newly described vascular proliferations, however, are difficult to differentiate from some of the angiosarcomas. Others are markers, occasionally, of serious conditions such as Fabry's Disease (angiokeratoma) and POEM's syndrome (glomeruloid hemangioma). Kaposi's sarcoma continues to be an enigma. The demonstration of Herpes virus 8 in this condition raises doubt about its neoplastic nature. The demonstration of endothelial differentiation of its nodular lesions is tenuous and its true nature remains unresolved. While physicians have known about post-mastectomy angiosarcomas from the origin of the radical mastectomy, a new group of unusual vascular proliferations of the mammary skin are being defined. These lesions arise in the setting of breast-conserving surgical treatment with adjuvant radiation therapy. The incubation period is usually 3 to 5 years, in contrast with the 10, or more, in classical cases of post-mastectomy angiosarcoma. These lesions usually are subtle, both clinically and histologically, in contrast with the "classical," dramatic presentation of mammary angiosarcoma. The spectrum of findings ranges from "simple" lymphangiectasia-like vascular proliferations to unequivocal angiosarcomas. The pathogenesis of these lesions remains a mystery. There are very few clues that allow one to separate hemangiomas from angiosarcomas. The presence of heterologous cellular elements and, particularly, well-developed smooth muscle components tends to favor a hemangioma. Similarly, the presence of thrombosis usually supports hemangioma. Nevertheless, there are no unequivocal or reliable individual diagnostic criteria. A thorough knowledge of the different conditions and their differential diagnoses eventually leads to the proper diagnosis in most cases.