Localized lymphomatoid papulosis: Unilesional lymphomatoid papulosis, regional lymphomatoid papulosis, and persistent agmination of lymphomatoid papulosis

Lymphomatoid papulosis (LYP), the most common primary cutaneous CD30-positive lymphoproliferative disorder, is heralded by multiple papular and nodular lesions at anatomically discontiguous cutaneous sites. The histologic patterns are protean. An uncommon form of LYP is one that is anatomically confined. Cases of unilesional LYP, regional LYP, and persistent agmination of LYP were encountered in the routine and consultative practices of Weill Cornell Medicine, Division of Dermatopathology. The clinical presentation, outcomes, light microscopic findings, and phenotypic profile are reviewed. There were 10 cases of LYP presenting as solitary plaques or nodules primarily occurring in older patients and without a relevant medical history in most. Most cases occurred at an acral site with many localized to the foot; the morphology was one of a necrotizing angiocentric type E pattern and borderline type C morphology. Two of the unilesional patients in our series went on to develop mycosis fungoides, one at the initial site of unilesional type A LYP, and the other at a discontiguous site. Excluding one case, the solitary lesions underwent complete regression; after the lesions regressed, some cases had no apparent recurrence. The second anatomically confined variant of LYP in our series was regional LYP exhibiting a type E morphology in two cases and a hybrid type A and granulomatous eccrinotropic morphology in one case. There was no subsequent development of lymphoma, nor was there any spread to additional anatomic sites. The final category was persistent agmination of LYP, whereby the agminated papules of LYP were superimposed on a plaque of cutaneous T-cell lymphoma represented by mycosis fungoides in two and follicular helper T-cell lymphoma in one. In conclusion, anatomically confined LYP defines an uncommon form of LYP, but it is an important one to recognize because the histology can be worrisome despite an indolent clinical course. The clinical presentation, the infrequent association with lymphoma/leukemia, and histology are similar to conventional LYP, although there appears to be a greater tendency for complete regression without recurrence, excluding cases of persistent agmination of LYP whereby the clinical course warrants categorization as a form of cutaneous T cell lymphoma (CTCL).

A Rare Perineurioma/Granular Cell Tumor Hybrid Peripheral Nerve Sheath Tumor

Hybrid peripheral nerve sheath tumors (PNSTs) are rare benign composite neoplasms demonstrating features of multiple endogenous nerve sheath cell types. Hybrid PNSTs with granular cell components are exceedingly rare. Only a handful number of hybrid PNSTs composed of granular cell tumor and perineurioma have been described to date. We present a rare hybrid of perineurioma and granular cell tumor and review the literature.

Two cases of congenital dermatomyofibroma

We present two infants with histologically confirmed congenital dermatomyofibromas. Congenital cases are rare with only one prior case reporting presence since birth. Given the benign nature of the lesions and propensity of dermatomyofibromas to resolve without intervention in young male patients, no additional treatments were pursued.

Signet-ring squamous cell carcinoma: a report of a rare variant and review of the literature

Signet-ring squamous cell carcinoma is a rare histological subtype of squamous cell carcinoma. The distinct morphologic appearance of this variant can mimic metastatic adenocarcinoma and impose a diagnostic challenge. Unlike its glandular counterpart, signet-ring cell variant of squamous cell carcinoma has a poorly characterized histopathogenesis with no known prognostic implication. We describe an additional case and review the literature.

Dermal eosinophilic infiltrate in junctional epidermolysis bullosa

Junctional epidermolysis bullosa (JEB) is a rare genodermatosis characterized by a split in the lamina lucida usually because of mutations in LAMA3, LAMB3 and LAMC2 resulting in absence or reduction of laminin-332. Rare subtypes of JEB have mutations in COL17A1, ITGB4, ITGA6 and ITGA3 leading to reduction or dysfunction of collagen XVII, integrin α6β4 and integrin α3. The classic finding under light microscopy is a paucicellular, subepidermal split. We describe the unusual presence of an eosinophilic infiltrate in the bullae and subjacent dermis in a neonate with JEB, generalized intermediate (formerly known as non-Herlitz-type JEB), discuss the histologic differential diagnosis for a subepidermal blister in a neonate, review the literature regarding cases of epidermolysis bullosa (EB) presenting with inflammatory infiltrates, and discuss mechanisms to explain these findings. This case highlights that eosinophils can rarely be seen in EB and should not mislead the dermatopathologist into diagnosing an autoimmune blistering disorder.

Sweet's syndrome--like neutrophilic lobular panniculitis associated with all-trans-retinoic acid chemotherapy in a patient with acute promyelocytic leukemia

Sweet's syndrome-like (Sweet's-like) neutrophilic panniculitis is usually idiopathic, but is frequently associated with hematologic, inflammatory, and immunologic disease. Drug-related cases of Sweet's syndrome have been reported. Of relevance, chemotherapy with the retinoid all-trans-retinoic acid (ATRA) infrequently induces Sweet's-like neutrophilic panniculitis that occurs concomitantly with neutrophilic differentiation. The pathologic features are limited to the adipose tissue or include both the dermis and the subcutaneous fat; the neutrophilic infiltrate can be observed in the lobules, the septae, or both. We present this case because of the unusual subcutaneous neutrophilic infiltrate consistent with Sweet's-like neutrophilic lobular panniculitis in a patient with acute promyelocytic leukemia receiving ATRA chemotherapy. This case highlights the important connection between ATRA and Sweet's syndrome.

Defining early mycosis fungoides

This editorial review summarizes the results of 5 meetings sponsored by the International Society for Cutaneous Lymphoma at which the clinicopathologic and ancillary features of early mycosis fungoides were critically examined. Based on this analysis, an algorithm was developed for the diagnosis of early mycosis fungoides involving a holistic integration of clinical, histopathologic, immunopathologic, and molecular biological characteristics. A novel aspect of this algorithm is that it relies on multiple types of criteria rather than just one, for example, histopathology. Before its finalization, the proposed diagnostic algorithm will require validation and possibly further refinement at multiple centers during the next several years. It is anticipated that a more standardized approach to the diagnosis of early mycosis fungoides will have a beneficial impact on the epidemiology, prognostication, treatment, and analysis of clinical trials pertaining to this most common type of cutaneous lymphoma.

Subungual myxoid pleomorphic fibroma

The authors report an example of pleomorphic fibroma in a unique site: the subungual space of the thumb. A 54-year-old man presented with paronychia and markedly thickened hyperkeratotic nail. The nail plate was removed, and an exophytic, red, friable, granulation tissue-like lesion was revealed subungually. The lesion was diagnosed clinically as pyogenic granuloma. Excisional biopsy was performed. Histologically, the lesion showed a hypocellular fibroma with myxoid areas and dilated blood vessels. Interspersed with ordinary appearing fibroblasts, there were bizarre, atypical fibroblasts with hyperchromatic and large, pleomorphic nuclei and multinucleated floret-like giant cells. These atypical cells showed strong immunoreactivity with antibodies against CD34 and vimentin. Occasional positivity was noted with factor XIIIa and alpha-1-antichymotrypsin, whereas no reactivity occurred with alpha-1-antitrypsin, actin, or S-100 protein. The entity of pleomorphic fibroma has been reported in many body sites; however, this is the first case to be reported in the subungual space.