A descriptive study of facial acanthosis nigricans and its association with body mass index, waist circumference and insulin resistance using HOMA2 IR.

INTRODUCTION: The term facial acanthosis nigricans (FAN) lacks definition of precise clinical and histopathological features. We present a descriptive study of patients with FAN to define pigmentary patterns and estimate the prevalence of obesity and insulin resistance in these cases. MATERIALS AND METHODS: It is a prospective study that included all patients with classical AN of the neck and/or other areas with facial acanthosis nigricans described as brown-to-black macular pigmentation with blurred ill-defined margins, found on the zygomatic and malar areas. The body mass index (BMI) and waist circumference (WC) of the included patients were used as parameters of obesity. Homeostatic Model of Assessment of Insulin Resistance (HOMA2 IR) was used as a parameter to evaluate insulin resistance. Histopathological features of the 6 skin biopsies that were possible were reviewed. RESULTS: Among the 102 included individuals, the patterns of facial pigmentation seen in addition to the classic pattern involving zygomatic and malar areas were a hyperpigmented band on the forehead in 59.80%, periorbital darkening in 17.64%, perioral darkening in 12.74%, and generalized darkening in 9.8% of cases. 85.29% of the males and 100% of the females were found to be obese. Varying degrees of insulin resistance was noted in 82.34% of the individuals. Six biopsies available for evaluation showed changes such as mild epidermal hyperplasia with prominent basal melanin, however, without the typical papillomatosis seen in AN of the flexures. CONCLUSION: We document an increased prevalence of obesity and insulin resistance in patients presenting with FAN and its presentations in addition to the classical description. We propose that FAN can be considered a cutaneous marker of insulin resistance and that HOMA2 IR can serve as a parameter of insulin resistance in such cases.

Multiarticular tophaceous gout with severe joint destruction: a pictorial overview with a twist.

Tophi are the visible dermatological signs of gout. A case of tophaceous gout in a middle-aged man with no other metabolic derangement is being presented with multiple tophi on the hands and feet overlying joints as well as on the fingers and toes. We thought it to be of educational value to demonstrate needle-like crystals of urate by polarizing microscopy. X-rays of hands and feet showed dramatic destructive changes. The patient presented with mottled hypopigmentation on anterior and posterior knees and dorsa of hands and feet where he applied hot "aankda" leaves and covered them with bandage resulting in irritant dermatitis with postinflammatory hypopigmentation. This proved to be a red herring in this case.

Carcinoma of lung with rhabdoid features.

Lung tumors with rhabdoid features, included as variants of large cell carcinoma in the 1999 World Health Organization classification of lung tumors, are rare and have an aggressive clinical course. We report 11 patients with primary lung tumors with rhabdoid features and review the literature on this uncommon tumor. We examined samples from 7 primary (6 resections, 1 biopsy) and 4 metastatic tumor samples. All specimens were stained with immunohistochemical stains for pancytokeratin (CK), cytokeratin 7 (CK7), cytokeratin (CK20), thyroid transcription factor-1 (TTF-1), and vimentin. The patients were 7 men and 4 women whose ages ranged from 35 to 70 years. Nine patients presented with respiratory symptoms, and 9 patients had a history of heavy smoking. One patient had TNM stage I tumor, 3 had stage III tumors, and 6 had stage IV tumors at presentation; tumor stage could not be determined in 1 patient. Histological examination of these tumors showed typical rhabdoid cells: large cells with abundant cytoplasm, a large eccentric nucleus with a central macronucleolus, and a rounded eosinophilic cytoplasmic inclusion that sometimes caused nuclear indentation. These cells constituted 10% to 90% of the tumor. The "parent" neoplasm was sarcomatoid carcinoma and adenocarcinoma in 4 cases each and was large cell undifferentiated carcinoma in 3 cases. Cytoplasmic staining in the rhabdoid cells was seen in 9 of 11 cases for CK, in 4 of 10 cases for CK7, and in all 11 cases for vimentin. Nuclear staining for TTF-1 in the rhabdoid cells was absent in all 11 cases, and cytoplasmic staining for CK20 was negative in the rhabdoid cells in all 10 cases studied. Of the 9 patients with available follow-up information, 8 died of disease, and 1 is alive with no evidence of disease 20 months after the initial diagnosis. We conclude that rhabdoid features can occur in a variety of lung tumors, including sarcomatoid carcinoma. Recognizing these lesions is important because of their possibly aggressive clinical course.

Factor X deficiency--a rare disorder.

Congenital factor X deficiency is a very rare inherited coagulation disorder. The clinical phenotype is of varying bleeding manifestations depending upon the level of factor activity. We describe a one and a half year old patient with severe deficiency (factor level less than 1%) who manifested with only easy bruisability and epistaxis that does not correlate with level of deficiency.

Thymic carcinoma with rhabdoid features.

A case of thymic carcinoma with rhabdoid differentiation is presented. A 67-year-old man who presented with chest pain and hemoptysis was referred to The University of Texas M. D. Anderson Cancer Center (Houston, TX). Radiologic studies revealed a large anterior mediastinal mass. After the initial biopsy and preoperative chemotherapy, a radical thymectomy revealed a stage III thymic carcinoma with a rhabdoid component. The rhabdoid component was characterized by large cells with an eccentric nucleus, prominent nucleolus, and typical paranuclear cytoplasmic inclusions. Immunohistochemical and electron microscopic studies confirmed the presence of rhabdoid cells with the paranuclear cytoplasmic inclusions staining for both pancytokeratin and vimentin. The patient was given postoperative chemotherapy and radiation. He has since developed metastases to the pelvis and is alive with disease at 20 months of follow-up. To our knowledge, this is the first reported case of thymic carcinoma with rhabdoid features.