Case Report: Human Subcutaneous Sparganosis in a Thai Migrant.

Human sparganosis is a cestode infection which is neglected as a differential diagnosis outside endemic countries. Diagnosis and therapy may be challenging depending on the clinical presentation and anatomic localization. The disease manifests predominantly as subcutaneous nodule(s) or intracranial mass lesion(s). Infection is primarily acquired by ingesting raw or undercooked amphibian or reptile flesh or by drinking water containing copepods. We report an unusual case of subcutaneous Spirometra erinaceieuropaei sparganosis presenting with two nonmigratory nodules in close proximity to each other on the right thigh of a Thai woman living in Switzerland.

Sebaceous Neoplasms With Rippled, Labyrinthine/Sinusoidal, Petaloid, and Carcinoid-Like Patterns: A Study of 57 Cases Validating Their Occurrence as a Morphological Spectrum and Showing No Significant Association With Muir-Torre Syndrome or DNA Mismatch Repair Protein Deficiency.

Sebaceous neoplasms with an organoid pattern (rippled, labyrinthine/sinusoidal, carcinoid-like, and petaloid) are rare. Previous studies suggested that the above patterns likely represent variations along a morphological continuum. The objectives of this study were to (1) validate this proposition by studying a large number of cases, (2) determine whether there are specific associations with clinical features, (3) establish their frequency, and (4) determine whether they have any association with Muir-Torre syndrome. Fifty-seven sebaceous neoplasms (54 sebaceomas and 3 sebaceous carcinomas) with organoid growth patterns were studied. These occurred in 36 men and 18 women (sex unknown in 3), with ages at diagnosis ranging from 22 to 89 years (mean, 63 years). All patients presented with a solitary nodule (mean size, 11 mm) on the head and neck area. Of the 57 tumors, 24 manifested a single growth pattern, 23 had a combination of 2 patterns, and 10 a combination of 3 patterns, indicating that these patterns are part of a morphological continuum of changes. The carcinoid-like pattern was the most frequent in the "monopatterned" neoplasms (13 cases), whereas the labyrinthine/sinusoidal pattern comprised most of the "polypatterned" lesions, in which various combinations occurred. Immunohistochemically, mismatch repair protein deficiency was detected in 3 of the 22 cases studied, whereas 5 of the 33 patients with available follow-up had an internal malignancy/premalignancy. In conclusion, sebaceous neoplasms with organoid growth patterns are predominantly sebaceomas having a predilection for the scalp, occurring as solitary lesions in elderly patients (male to female ratio of 2:1). Such patterns are expected to be found in a quarter of sebaceomas. In most cases, more than one of the organoid patterns is present. These lesions do not appear to be associated with internal malignancy or mismatch repair deficiency in most cases. However, confirmation of the absence of any significant association with Muir-Torre syndrome syndrome will require genetic studies.

Squared-Off Nuclei and "Appliqué" Pattern as a Histopathological Clue to Periocular Sebaceous Carcinoma: A Clinicopathological Study of 50 Neoplasms From 46 Patients.

The histopathological diagnosis of periocular sebaceous carcinoma can be difficult in poorly differentiated cases showing few mature sebocytes. The authors examined 50 periocular sebaceous carcinomas from 46 patients to determine the frequency of 2 features seen in this neoplasm, namely cells with squared-off nuclei and so-called "appliqué" pattern (peritumoral subnecrosis of peripherally located neoplastic cells). Neoplastic cells with squared-off nuclei were found in varying numbers in both the intraepithelial and dermal (invasive) components in all neoplasms, whereas the appliqué pattern was observed in a third of the cases. It is concluded that these features, taken together, may serve as a clue for the diagnosis of periocular sebaceous carcinoma.

Hidradenoma Papilliferum: A Clinicopathologic Study of 264 Tumors From 261 Patients, With Emphasis on Mammary-Type Alterations.

Hidradenoma papilliferum (HP), also known as papillary hidradenoma, is the most common benign lesion of the female anogenital area derived from anogenital mammary-like glands (AGMLG). HP can be viewed conceptually as the cutaneous counterpart of mammary intraductal papilloma. The authors have studied 264 cases of HP, detailing various changes in the tumor and adjacent AGMLG, with emphasis on mammary-type alterations. In many HP, the authors noticed changes typical for benign breast lesions, such as sclerosing adenosis-like changes, usual, and atypical ductal hyperplasia. Almost in a third of cases, remnants of AGMLG adjacent to the lesion were evident, manifesting columnar changes reminiscent of those seen in breast lesions. This study shows that the histopathological changes in HP run a broad spectrum comparable with that in the mammary counterpart and benign breast disease.

Trauma-Induced Cutaneous Focal Mucinosis of the Mammary Areola: An Unusual Presentation.

Cutaneous focal mucinosis (CFM) is a localized form of cutaneous dermal mucinosis clinically presenting as an asymptomatic skin-colored papule or nodule. The etiopathogenesis of CFM is unclear, but it is thought to represent a reactive lesion. Although trauma has been suspected as a triggering factor, it has never been proven in cases of CFM. We report 2 male patients with trauma-induced CFM arising at the mammary areola, which is an unusual site for CFM. Both male patients presented with a solitary nodular lesion of up to 2 cm in diameter at the right areola. Histology was characterized by circumscribed abundant dermal mucin deposits in a polylobulated pattern without an increased number of fibroblasts or capillaries and with absence of an inflammatory infiltrate. Alcian blue stain at pH 2.5 highlighted the mucin deposits. Immunohistochemistry showed partial expression of FXIIIa by 30% of the stromal cells, but no reactivity for CD34, smooth muscle actin, desmin, CD68 and S-100. A history of trauma (laser-based epilation, piercing) preceded the development of CFM in both patients. Surgical excision resulted in complete remission without recurrence. Follow-up in both our patients did not reveal recurrences. CFM has to be distinguished from benign and malignant myxoid neoplasms.

Hybrid peripheral nerve sheath tumors, including a malignant variant in type 1 neurofibromatosis.

The authors report a small case series of hybrid nerve sheath tumors occurring in the setting of type 1 neurofibromatosis. Four lesions were benign and consisted of plexiform neurofibromas with considerable areas of perineuriomatous differentiation in patients with type 1 neurofibromatosis. In these lesions, biphasic (Schwannian and perineuriomatous) differentiation was apparent on immunohistochemistry, with the perineuriomatous areas staining for epithelial membrane antigen, glut-1, and claudin-1 and being negative for S-100 protein. Three patients were members of a single family, with a history of various malignant neoplasms. Included in the series is 1 hybrid lesion in which neurofibromatous and perineuriomatous areas were clearly visible on hematoxylin- and eosin-stained slides. The lesion was unique in that it manifested malignant change in the S-100 protein-positive component, which was classified as malignant peripheral nerve sheath tumor. The malignant component showed areas with an epithelioid cell morphology.

Primary cutaneous B-cell lymphomas.

Cutaneous B-cell lymphomas (CBCL) are the second most common form of primary cutaneous lymphomas. The cutaneous follicle center lymphoma and the cutaneous marginal zone lymphoma (extranodal MALT type lymphoma) account for the vast majority of CBCL and manifest with nodules. These two lymphoma entities have an indolent, slowly progressive course and an excellent prognosis despite a high rate of recurrences. In contrast, cutaneous diffuse large B-cell lymphoma, leg type, and other rare forms of CBCL display an impaired prognosis and therefore require to be treated with multiagent chemotherapy and anti-CD20 monoclonal antibodies in most cases. Clinico-pathologic correlation, histology with immunohistochemical profile and genotyping as well as staging examinations are crucial diagnostic elements in the work-up of CBCL.

Necrotizing infundibular crystalline folliculitis: a clinicopathological study.

BACKGROUND: Necrotizing infundibular crystalline folliculitis (NICF) is a folliculocentric disorder associated with filamentous crystalline deposits, enclosed by parakeratotic columns within the partly necrotic follicular ostium and infundibulum. There are only very few data published about this disorder of unknown origin. OBJECTIVE: We sought to determine the clinicopathological features and pathogenetic aspects of NICF. METHODS: Clinicopathological characterization of 9 patients with NICF and a second group of 7 patients with coincidental findings of NICF in the vicinity of epithelial skin neoplasms was conducted. RESULTS: Clinically, NICF is characterized by multiple waxy papules with predilection for the forehead (56%), neck, and back. Birefringent crystalline deposits were present in the follicular ostia and enclosed by parakeratotic columns in all cases. The necrosis of follicular epithelium was found in 89% and perifollicular neutrophilic infiltrate in 22% of the biopsy specimens. Both yeasts and gram-positive bacteria were identified within the affected follicles in 56% in the first group and 86% in the second group of coincidental NICF. LIMITATION: This was a single-center retrospective study. CONCLUSIONS: NICF is both a distinct entity and an epiphenomenon in the context of other disorders. In regard to the common association with yeasts and gram-positive bacteria in the affected follicles, we hypothesize that NICF is pathogenetically linked to these organisms, which is supported by resolution of the lesions after topical or systemic antimycotic treatment.

Cutaneous hidradenocarcinoma: a clinicopathological, immunohistochemical, and molecular biologic study of 14 cases, including Her2/neu gene expression/amplification, TP53 gene mutation analysis, and t(11;19) translocation.

We present a series of 14 cases of cutaneous hidradenocarcinomas. The patients included 6 women and 8 men ranging in age at diagnosis from 34 to 93 years. All but 1 patient presented with a solitary nodule. There was no predilection site. One patient presented with multiple lesions representing metastatic nodules. Of 12 patients with available follow-up, 2 died of disease, whereas the remaining 10 patients were alive but 3 of them experienced a local recurrence in the course of the disease. Grossly, the tumors ranged in size from 1.2 to 6 cm. Microscopically, of the 14 primary tumors, 9 showed low-grade cytomorphology, whereas the remaining 5 neoplasms were high-grade lesions. The residuum of a hidradenoma was present in 5 of the 14 primaries. The mitotic rate was highly variable, ranging from 2 to 64 mitoses per 10 high-power field. The cellular composition of the tumors varied slightly, with clear cells, epidermoid cells, and transitional forms being present in each case. In 1 case, there was metaplastic transformation into sarcomatoid carcinoma. Glandular differentiation varied from case to case and appeared most commonly as simple round glands or as cells with intracytoplasmic lumens. Necrosis en masse was detected in 8 specimens. One specimen represented a reexcision and was unusual as it showed a well-demarcated intradermal proliferation of relatively bland clear cells accompanied by an overlying intraepidermal growth of clear cells resembling hidradenoacanthoma simplex. Despite the bland appearance, the tumor metastasized to a lymph node. Immunohistochemically, 5 of the 8 specimens studied for Her2/neu expression were negative, whereas 3 specimens from 2 cases yielded score +2, but all the 3 specimens with score 2+ subsequently proved negative for Her2/neu gene amplification by fluorescence in situ hybridization. Of 10 primaries studied, 4 tumors showed positive p53 immunoreaction in more than 25% of the cells comprising the malignant portion of the lesions, in 2 cases, a minority of the neoplastic cells (10%-20%) demonstrated nuclear staining, whereas the remaining 4 cases were negative. Of 9 specimens of hidradenocarcinoma studied for TP53 mutations, 2 harbored mutations, whereas the remaining 7 specimens showed the wild-type sequence. Of 11 specimens studied for translocation t(11;19), 2 cases harbored the translocation. It is concluded that cutaneous hidradenocarcinomas show some microscopic heterogeneity and comprise both low- and high-grade lesions that cytologically are similar to their benign counterpart, the hidradenoma. Within the spectrum of low-grade lesions, there seem to exist tumors almost indistinguishable from hidradenomas but still being capable of regional or distant metastasis. Similar to hidradenomas, hidradenocarcinomas show a t(11;19) translocation, but it is a significantly rarer event. Even rarer is the amplification of the Her2/neu gene. Of note is the relatively low frequency of TP53 mutations despite a high rate of p53 protein expression at the immunohistochemical level.

Histopathology of anti-p200 pemphigoid.

Anti-p200 pemphigoid is an autoimmune subepidermal blistering disease characterized by circulating and tissue-bound antibodies against a 200-kd glycoprotein (p200) of the human dermis. We reviewed 10 lesional biopsies from seven patients with anti-p200 pemphigoid in an attempt to define typical histopathologic features of this disease. All biopsy specimens showed subepidermal blistering and a moderate to dense inflammatory infiltrate in the upper dermis. Immunohistochemical analysis localized type IV collagen to the dermal side of the blister, suggesting that split formation occurred within the lamina lucida of the cutaneous basement membrane. The inflammatory infiltrate was composed almost exclusively of neutrophils in six biopsies and contained a mixture of neutrophils and eosinophils in the remaining four. In three specimens, microabscess formation in the papillary dermis adjacent to the blister cavity was noted. Neutrophilic and eosinophilic spongiosis was found in five and three biopsies, respectively. We conclude that histopathology of anti-p200 pemphigoid is characterized by subepidermal blistering and a superficial inflammatory infiltrate, which is usually dominated by neutrophils but occasionally contains significant numbers of eosinophils. While this microscopic picture mimics that of linear IgA disease, dermatitis herpetiformis, or bullous pemphigoid, it should also alert a histopathologist to the possibility of anti-p200 pemphigoid and prompt immunofluorescence and immunoblotting studies for definite diagnosis or exclusion of this autoimmune subepidermal blistering disease.

Axillary acne agminata (lupus miliaris disseminatus faciei with axillary involvement).

Acne agminata (AA) and lupus miliaris disseminatus faciei (LMDF) have been used to describe very similar clinical conditions and it is now generally accepted that they are synonymous. The cause of these disorders has not been determined. Clinically the disease presents with often agminated redbrown to yellow papules which occasionally become pustular. Microscopically, superficial granulomatous inflammation with perifollicular caseating granulomas is the hallmark. Axillary involvement with LMDF has rarely been reported; in this area AA has been the preferred term. When only the axillae are affected, it may be difficult to distinguish acne agminata from other granulomatous diseases, especially from granulomas caused by antiperspirants containing aluminumzirconium complexes. We describe a 36-year-old woman with axillary acne agminata.