CD56 staining in Merkel cell carcinoma and natural killer‐cell lymphoma: magic bullet,diagnostic pitfall,or both?

Background: Antibodies to CD56 label natural killer (NK) cell lymphomas and neuroendocrine tumors such as Merkel cell carcinoma (MCC). In MCC altered by crush artifact or obscured by lymphocytes, the histologic features coupled with CD56 positivity can lead to an erroneous impression of NK‐cell lymphoma. Methods: Eighteen cases of MCC were stained for CD56, CK20, MNF116, and pankeratin. The results were compared to histologic features and CD56 staining pattern of three NK‐cell lymphomas. Results: Three of 18 cases of MCC histologically resembled lymphoma, and CD56 positivity with CD3 and CD20 negativity initially raised the possibility of NK‐cell lymphoma. Two additional cases were obscured by dense inflammation, again suggesting the diagnosis of lymphoma. Seventeen of 18 MCC labeled for CD56 and an equal number stained for CK20. All MCC tested were positive for CAM5.2 (14/14) and MNF116 (17/17). Antibodies to pankeratin labeled only one of 18 MCC. Staining for CD56 was stronger in MCC than NK‐cell lymphomas. Conclusions: CD56 is a sensitive marker for MCC as well as for NK‐cell lymphoma, but is not specific. Importantly, CD56 positivity in crushed or inflamed biopsies of MCC may lead to an erroneous impression of NK lymphoma. Awareness of this potential pitfall will prevent misdiagnosis.     

Psoriasis associated with idiopathic CD4+ T‐cell lymphopenia: a regulatory T‐cell defect?

Idiopathic CD4⁺ lymphocytopenia (ICL) is a rare immunodeficiency syndrome of unknown origin for which the increased risks of opportunistic infections and of malignancies have been well established; however, skin dysimmune diseases, including psoriasis, have been scarcely reported up to now. We report herein the severe course of psoriasis in four patients with ICL, and show evidence for a defect in the skin recruitment of regulatory CD4⁺FoxP3⁺ T cells. These data raise the apparent paradigm of the occurrence of a severe immunomediated disease together with a profound T‐cell defect, a model that might also apply to other immune deficiencies associated with psoriasis.     

‘Activation‐induced cell death’: a special program able to preserve the homeostasis of the skin?

The 'activation-induced cell death' (AICD) is a molecular system leading to death of antigen-activated T lymphocytes, in order to avoid accumulation of harmful cytokine-releasing cells. This article reviews both the molecular mechanisms working in AICD and the role played by such mechanisms in preventing a number of skin diseases. Specifically, because AICD removes activated and autoreactive T cells through a CD95-/CD95-L-mediated suicide, skin diseases were scrutinized in which such valuable machinery could be lacking. Indeed, at least some inflammatory skin diseases, including psoriasis and atopic dermatitis, can be sustained by an increased survival of activated T lymphocytes associated with deficient CD95-/CD95-L-mediated AICD of such strong pro-inflammatory cells. In addition, autoreactive skin diseases, including, e.g. alopecia areata, lichen planus and other lichenoid tissue reactions, can be related to autoreactive T lymphocytes which could be unable to undergo CD95-/CD95-L-mediated AICD. Finally, a lack of AICD may be executive even in favoring cutaneous T cell lymphoma. Thus, because inflammatory, autoreactive and neoplastic skin diseases can be associated with a deficient CD95-/CD95-L-mediated suicide of activated T cells, AICD is likely to represent a fundamental program to preserve the homeostasis of the skin. Therapeutic approaches able to restore the AICD machinery promise to successfully treat such relevant skin diseases.     

Adult Henoch-schönlein purpura in a patient with myelodysplastic syndrome and a history of follicular lymphoma

GOAL: To understand Henoch-Sch?nlein purpura (HSP) to better manage patients with the condition. OBJECTIVES: Upon completion of this activity, dermatologists and general practitioners should be able to: 1. Describe the criteria for diagnosing HSP. 2. Explain the association of malignancy and HSP. 3. Discuss the prevalence of HSP in adults. Henoch-Sch?nlein purpura (HSP) is a systemic leukocytoclastic vasculitis involving arterioles and venules most commonly in the skin, glomeruli, and gastrointestinal tract. In skin, it is associated with IgA deposition around dermal blood vessels. While an exact cause of HSP has not been elucidated, several processes have been implicated in its development, including infections; drugs; and allergic, rheumatologic, and neoplastic diseases. We present a 57-year-old woman with a history of follicular lymphoma who developed HSP likely associated with myelodysplastic syndrome. This case is clinically significant because the patient was thought to be in remission of her hematologic disease until her skin findings prompted further evaluation. Her diagnosis of HSP was based on clinical presentation with palpable purpura and abdominal pain, and was confirmed with biopsy and immunohistochemical analyses of purpuric papules demonstrating leukocytoclastic vasculitis and strong anti-IgA labeling in the dermal endothelial cells consistent with immunocomplex deposition. The occurrence of vasculitis and malignant disease in the same patient often is difficult to interpret, as some patients may exhibit both diseases independently and by chance, while others may have vasculitis as a paraneoplastic syndrome. We review cases of adult HSP associated with malignancy in the literature.     

Segmental anhidrosis with hyporeflexia associated with congenital spinal deformity: a Ross's syndrome variant or inverse Horner's syndrome?

A 39-year-old soldier presented with anhidrosis affecting both upper extremities below the shoulders, the right side of the trunk below the third rib in front and the third vertebra on the back, and the left lower extremity below the inguinal ligament since 1992. Ten years later in 2002, he was also found to have bilateral absence of Achilles reflex and decreased right knee jerk. In addition, the patient was found to have congenital spinal abnormalities in the form of block of vertebrae C3-C4; decreased disc space C4-C5; and break in pars interarticularis L5-S1 with decreased disc space. A total of seven cases of Ross syndrome, Holmes-Adie syndrome (tonic pupil with lost tendon jerks) with segmental anhidrosis, have been described in the literature. Our case, however, did not have any pupillary abnormality. A case of progressive isolated segmental anhidrosis has also been described. The association of congenital spinal abnormality, which may be pathognomonic in the causation of this progressive sudomotor degeneration, is quite interesting in our case. The distribution of anhidrosis on the right side is just below the level of sweating loss sometimes described in lesions of superior sympathetic cervical ganglion in Horner's syndrome.     

Parry–Romberg syndrome associated with borreliosis: could photochemotherapy halt the progression of the disease?

Parry-Romberg syndrome (PRS) or progressive hemifacial atrophy is a rare entity characterized by unilateral atrophy of the skin, subcutaneous tissue and sometimes bone and cartilage. Although this syndrome has overlapping features of scleroderma 'en coup de sabre', it shows little or no sclerosis and may affect the entire distribution of the trigeminal nerve including the eye and tongue. As the pathogenesis is unknown, no effective therapy exists. We present here the third case of PRS associated with borreliosis and more interestingly two cases whose progressive course have been stabilized with gel PUVA therapy.     

Is the human skin a pheromone‐producing organ?

It is controversial whether or not humans convey specific compounds within their body odours which can potentially affect the physiology and behaviour of others. Such compounds are called pheromones and have been discovered in many other species, including mammals. It has been suggested that humans might have a special organ within their nose that can transmit such chemosensory information. However, the evidence for this organ is highly questionable. In any case, the main olfactory system is a highly diverse system, capable of transmitting pheromonal information. So far, no single substance has been found that acts as a chemical messenger for erotic attraction. On the other hand, studies investigating the pheromonal properties of natural complex body odour have proven that it does deliver information about the sender and that it has an effect on the physiology and likely behaviour of other humans. Its significance for human mating preferences probably lies not in driving them to choose the right mate but rather in warning them not to choose the wrong one.     

A case of Sézary's syndrome associated with granulomatous lesions,myelodysplastic syndrome and transformation into CD30-positive large-cell pleomorphic lymphoma

Sézary's syndrome (SS) is a leukaemic variant of mycosis fungoides, a cutaneous T-cell lymphoma showing distinct clinical, histological, immunological, and genotypic features. We report a 10-year follow-up of a patient with SS exhibiting unusual features such as granulomatous skin lesions, transformation to a CD30-positive large-cell pleomorphic T-cell lymphoma, and development of myelodysplastic syndrome and review the cases of SS reported in the literature with these unusual and rare complications.     

Histiocytic sarcoma with secondary involvement of the skin and expression of CD1a: evidence of indeterminate cell differentiation?

BACKGROUND: Histiocytic sarcoma is an exceedingly rare malignant neoplasm composed of cells with a monocyte/macrophage phenotype. In the current nosology of histiocytic neoplasms, histiocytic sarcoma is separate from indeterminate cell histiocytosis, a generally benign disorder characterized by proliferation of a CD1a+ and S-100+ population of cells lacking Birbeck granules usually limited to the skin. METHODS: We present a case of histiocytic sarcoma in a 64-year-old man presenting as a peritonsillar mass and secondarily involving the skin. RESULTS: The malignant cells in the extracutaneous foci of disease expressed macrophage-associated antigens including S-100 but were CD1a-. The malignant cells in the skin coexpressed CD1a and S-100 but lacked ultrastructural features of Langerhans cells, findings indicative of indeterminate cells. CONCLUSIONS: We discuss the clinical and histopathologic differential diagnosis in association with prior reported cases of histiocytic sarcoma, particularly in cases involving the skin and cases expressing the Langerhans cell-associated antigen CD1a.     

Fibroblastic Rheumatism: a variant of non‐langerhans cell histiocytoses?

The following letter was previously published, in the May/June 2003 issue of PEDIATRIC DERMATOLOGY, with the omission of the first word of the title, which was essential for conveying the authors’ meaning, thus making their thoughts irretrievable by others interested in this issue. Therefore, the Editor has opted to republish this letter, with its correct title, and to extend to its authors our most sincere regrets for the error.