Pacinian corpuscle hyperplasia: A review of the literature.

OBJECTIVE: Pacinian corpuscle hyperplasia typically presents as a tender nodule on the volar aspect of the palm or digit, often after trauma. Histologically, it presents as one to multiple normal-sized to enlarged Pacinian corpuscles in the deep dermis or subcutaneous adipose tissue. Given its rarity, its pathogenesis is debated and nomenclature is poorly defined. Herein, we present a case of Pacinian corpuscle hyperplasia and review the current literature. METHODS: A literature review was conducted using PubMed with the following search terms: Pacinian corpuscle hyperplasia, Pacinian corpuscle neuroma, Pacinioma, Pacinian corpuscle hypertrophy, and heterotopic Pacinian corpuscles. All case reports and case series were reviewed for histopathologic evidence of true Pacinian corpuscle hyperplasia. Cadaveric studies, cases without true Pacinian corpuscles, and noncutaneous cases were excluded from our analysis. RESULTS: Sixty patients with Pacinian corpuscle hyperplasia of the hands and feet (65 cases, some with >1 location) were reviewed. The mean age of presentation was 49.5 years, and women accounted for 60% of cases. Pain was the most commonly reported symptom (55 of 65 cases; 84.6%). Forty-five cases (69.2%) were localized to a digit, most commonly the second digit (17 of 65 cases; 26.2%), and 18 of 65 cases (27.6%) affected the palm, primarily the distal palm. Surgical excision was curative in 50 of 65 cases (76.9%). CONCLUSION: Although relatively uncommon, Pacinian corpuscle hyperplasia should be considered in the differential diagnosis of a tender nodule on the digit or distal palm, particularly after trauma.

Acquired blue nevus of the nail bed.

Blue nevi are benign proliferations of melaninproducingdendritic melanocytes located in thedermis. These nevi tend to occur mostly on the skin,predominantly on the head and neck, dorsal aspectsof the distal extremities, and the sacral area, butcan also occasionally appear on mucosal surfaces.Blue nevi of the nail apparatus are uncommon. Themajority originate in the nail matrix where there is ahigher density of melanocytes. Herein we report ona 47-year-old man with a rare common blue nevus ofthe nail bed, an area with low melanocyte density. Athorough review of the English language literaturefound no documented cases of acquired blue nevioriginating in the nailbed of the toe.

Nodular cystic fat necrosis with calcification in a patient with juvenile dermatomyositis.

Nodular cystic fat necrosis is a rare, benign form of encapsulated fat necrosis with distinct histology, characterized by cystic fat necrosis with lipomembranous changes and, in later stages, calcification. We report the case of a 7-year-old child with juvenile dermatomyositis who presented with three asymptomatic, firm, mobile nodules on the arms and neck. Histology was consistent with nodular cystic fat necrosis with prominent calcification. This is an unusual presentation of this entity because it has never been previously reported in association with juvenile dermatomyositis.

Congenital multiple clustered dermatofibroma in a 12-year-old girl.

Congenital multiple clustered dermatofibroma (MCDF) is a rare, idiopathic, benign tumor presenting at birth as an asymptomatic hyperpigmented patch that is stable until puberty, at which time it enlarges and develops papules. Ultimately, MCDF appears to follow a stable, benign course. We present a case of a 12-year-old girl with congenital MCDF. To our knowledge, this is only the third reported case of congenital presentation of MCDF and the only case featuring atrophoderma-like depression.

Prominent papillary dermal edema in dermatophytosis (tinea corporis).

BACKGROUND: Commonly described histologic 'clues' to the diagnosis of dermatophytosis include neutrophils in the stratum corneum and/or epidermis, compact orthokeratosis and identification of fungal hyphae between two zones of cornified cells. Prominent (striking) papillary dermal edema (PPDE) is not commonly reported with dermatophytosis (tinea corporis). METHODS: We observed an index case in which PPDE was the salient histologic finding in lesions of tinea corporis. Fifteen additional cases of tinea corporis with PPDE were diagnosed in our dermatopathology laboratory over a 9-year period. The clinical and histologic findings were reviewed. RESULTS: All 16 cases occurred on the extremities of women, 11 of whom had skin of color. The submitted clinical differential diagnoses varied widely, but included some of the diseases 'classically' associated with PPDE, as well as other blistering eruptions. In several cases, only a few dermatophyte hyphae were identified in tissue sections. CONCLUSIONS: Our case series serves as a reminder that dermatophytosis should be strongly considered in the differential diagnosis of lesions with PPDE. Fungal culture may be helpful in patients whose biopsies show PPDE, negative periodic acid-Schiff (PAS) stains and who fail to respond to conventional anti-inflammatory therapy. This study lends support for the routine use of PAS stains in biopsies of inflammatory dermatoses.

Cutaneous ganglioneuroma.

Primary cutaneous ganglioneuroma is an extremely rare tumor. We report a case of solitary cutaneous ganglioneuroma on the back of a 75-year-old woman.

Cutaneous metastasis of renal cell carcinoma with Zellballen-like inflammatory reaction pattern on immunohistochemical studies.

Skin tumors show variable infiltration by subtypes of inflammatory cells. The composition of these cellular infiltrates, particularly tumor-associated macrophages and dendritic cell numbers, may be responsible for skin tumor progression or regression. In addition, these cells may give rise to diagnostic dilemmas on immunohistochemical studies. The authors report on the local inflammatory reaction to a metastatic renal cell carcinoma to the skin. Histologic examination and immunohistochemical studies demonstrated zellballen-like changes with S-100-positive spindled cells identified around and within tumor cell nests. The role of tumorassociated macrophages and dendritic cells in the skin is discussed.

Infectious eccrine hidradenitis caused by Nocardia.

Neutrophilic eccrine hidradenitis is a nonspecific clinical reaction pattern classified as a neutrophilic dermatosis that typically occurs in the setting of chemotherapy for hematologic malignant disease. Neutrophilic eccrine hidradenitis more rarely has been reported in association with infectious agents, including Serratia, Enterobacter, Staphylococcus, and HIV. We describe the first case of infectious eccrine hidradenitis occurring in a patient with cutaneous Nocardia infection.

The sensitivity and specificity of "caterpillar bodies" in the differential diagnosis of subepidermal blistering disorders.

Caterpillar bodies are eosinophilic, elongated, segmented bodies located within the roofs of blisters and are considered to represent a specific histopathologic feature of porphyric bullous eruptions, including porphyria cutanea tarda and erythropoietic protoporphyria. The possibility that similar or identical bodies may be present in other disorders prompted further study exploring the specificity of caterpillar bodies in the differential diagnosis of subepidermal vesiculobullous disorders. Seventy-six cases exhibiting subepidermal clefting were reviewed by light microscopy. "Classic" caterpillar bodies were present in porphyria cutanea tarda (6 of 14) and 1 case representing either venous stasis-associated bulla or possibly bullosis diabeticorum. Caterpillar body-like clusters were present in porphyria cutanea tarda (5 of 14), erythropoietic protoporphyria (1 of 3), bullous pemphigoid (7 of 24), and junctional or dystrophic epidermolysis bullosa (3 of 5). In some cases, classic caterpillar body and caterpillar body-like clusters coexisted in a blister roof. Caterpillar bodies or caterpillar body-like clusters were not identified in any cases of dermatitis herpetiformis, linear IgA bullous dermatosis, bullous erythema multiforme, epidermolysis bullosa acquisita, or wound-healing reactions. In contrast to caterpillar bodies, caterpillar body-like clusters were negative for PAS or Type IV collagen stains. In conclusion, caterpillar bodies appear to represent a specific feature of porphyria cutanea tarda (specificity, 98%) but were present in less than half of those cases in this study (sensitivity, 43%). Caterpillar body-like clusters are less specific and may be present in porphyria cutanea tarda, erythropoietic protoporphyria, pseudoporphyria, bullous pemphigoid, epidermolysis bullosa, and epidermolysis bullosa acquisita.