Axillary hyperhidrosis: eccrine or apocrine?

We review the literature regarding axillary hyperhidrosis, discuss normal sweat gland function and postulate on the respective roles of the eccrine, apocrine and apo-eccrine glands in the pathophysiology of excessive axillary sweating.     

Merkel cell tumor in a trichilemmal cyst: collision or association?

An 86-year-old white male presented with an erythematous, painless, slowly growing, and firm left thigh nodule. Histologic examination revealed a dermal proliferation of monomorphous cells arranged in trabeculae, nests, and sheets with an infiltrative growth pattern. The cells had a high nuclear-cytoplasmic ratio, finely granular nuclear chromatin, and nuclear molding. Numerous mitotic figures, apoptotic cells, and individual cell necrosis were present; lymphovascular invasion was identified. The tumor was attached, demonstrating pagetoid intraepithelial migration, to a follicular cyst lined by squamous epithelium, lacking a granular cell layer and filled with compact keratinous content, diagnostic of trichilemmal cyst. Immunohistochemical study revealed that tumor cells expressed pan-cytokeratin (CK), chromogranin, synaptophysin, neuron-specific enolase, and CK20 (dotlike staining pattern), thus supporting the diagnosis of Merkel cell carcinoma. The association of Merkel cell carcinoma with a cyst is an exceptionally rare occurrence. As a result of the prominent involvement of the cyst wall by tumor cells, we favor that in this case carcinoma arose in the trichilemmal cyst rather than being a collision tumor. This hypothesis is also supported by the recent observation that Merkel cells are frequently present within normal hair follicles, especially in the isthmic portion that corresponds with the area of origin of the trichilemmal cyst.     

Reticulated acanthoma with sebaceous differentiation: another sebaceous neoplasm associated with Muir–Torre syndrome?

Reticulated acanthoma with sebaceous differentiation (RASD) represents a rare benign cutaneous epithelial neoplasm with sebaceous differentiation. There has been much speculation about the relationship between RASD and Muir–Torre syndrome (MTS). We report a 53 year‐old man who presented with RASD in addition to a prior history of sebaceous adenomas. Immunohistochemically, the tumour cells in the RASD and sebaceous adenomas showed a significantly reduced MSH6 protein expression, whereas there was no loss of MLH1, MSH2 and PMS2. This benign neoplasm, which can be mistaken for various other cutaneous lesions with sebaceous differentiation, deserves wider recognition for its possible association with MTS.     

Eccrine syringofibroadenoma and clear cell acanthoma: an association by chance?

A 58-year-old white woman with stasis dermatitis developed a solitary, slowly growing keratotic nodule of the dorsum of the foot. The excision biopsy specimen of this lesion showed a biphasic pattern of eccrine syringofibroadenoma and clear cell acanthoma. Such a previously unreported association is neither necessarily by chance nor necessarily a collision. Because a reactive histogenesis has been postulated for both eccrine syringofibroadenoma and clear cell acanthoma, this case could represent a morphologically biphasic pattern of epidermal and ductal hyperplasia as a consequence of the stasis-induced chronic inflammation coupled with the footwear-induced chronic trauma.     

Psoriasis: Psychosomatic,somatopsychic, or both?

Psoriasis is a chronic inflammatory disorder characterized by substantial psychiatric comorbidity. Historically, anecdotal observations have suggested that psychosocial distress can trigger flares of psoriasis, but over the past several decades, high-quality data from experimental studies support the assertion that stress plays a critical role in the pathogenesis of psoriasis. There may be a subset of patients unable to elicit an appropriate immunosuppressive response to stress through upregulation of cortisol, with resultant exacerbation of their psoriasis. Other notable studies revealed that key neuromodulators, including substance P, calcitonin gene–related peptide, vasoactive intestinal peptide, and nerve growth factor may be potent regulators of neurogenic inflammation that induce psoriasis flares through a stress-mediated mechanism. Preliminary trials in humans that examine psychosocial interventions to reduce stress, as well as animal studies targeting specific neuropeptides, provide support for the concept that alteration of pathways mediated by the stress response represents novel forms of therapy in the management of psoriasis.     

Relapse, reinfection or inadequate MDT ?

Relapse by all standard definitions is reported in a middle aged woman after PB MDT. Since she belonged to a family of treated leprosy sufferers (husband and his elder brother) and her daughter has now developed infectious type of leprosy, the possibility of reinfection can also not be ruled out.     

Systemic lupus erythematosus or infection with HIV,or both?

The features of both HIV infection and connective tissue disease are often nonspecific and may mimic other disorders as well as each other. We treated a patient with presumed systemic lupus erythematosus (SLE) for 4 years, who finally admitted to longstanding infection with HIV. The coexistence of SLE and HIV is unusual and has, although reported in the rheumatological journals, not often been discussed in the dermatological literature.     

Muir-Torre Syndrome / Turcot Syndrome overlap? A patient with sebaceous carcinoma, colon cancer, and a malignant astrocytoma

The Muir-Torre Syndrome is characterized by the clinical constellation of sebaceous neoplasms, keratoacanthomas, and internal malignancies caused by a defect in DNA mismatch repair. Another mismatch repair defect causes Turcot syndrome, which manifests with colorectal and central nervous system neoplasms. We wish to report a case in which the manifestations of both syndromes were observed in the same patient. We further discuss the possible genetic basis for this overlap.