Squamoid eccrine ductal carcinoma: clinical, histological and immunohistochemical features.

Squamoid eccrine ductal carcinoma (SEDC) is a cutaneous adnexal malignancy that is histologically challenging to distinguish from squamous cell carcinoma. We report three cases of this rare entity and review the present literature regarding clinical, histological, and immunohistochemical features. Patients presented with a single nodule or plaque lesion on their back and temple. The shave biopsies for Patient A and C were interpreted as SEDC. Patient B's initial shave biopsy was interpreted as probable surface of squamous cell carcinoma, and subsequent excision revealed SEDC. Ductal differentiation was confirmed by positive expression of epithelial membrane antigen and carcinoembryonic antigen immunostains in all three patients. Review of the 67 previously reported cases emphasizes the importance of diagnosing SEDC accurately and promptly given its potential for distant metastasis and mortality. Perineural or lymphatic invasion is associated with higher rate of recurrence or metastasis. There should be high pathologic suspicion for SEDC in an elderly patient presenting with a palpable lesion, even if located outside of the head and neck area, particularly when there is suggestion of ductal differentiation in a sample of a squamous neoplasm.

Kikuchi-Fujimoto disease preceded by lupus erythematosus panniculitis: do these findings together herald the onset of systemic lupus erythematosus?

Kikuchi-Fujimoto disease (KFD), also known as histiocytic necrotizing lymphadenitis, is a rare disorder that must be distinguished from systemic lupus erythematosus (SLE). Although a minority of patients with KFD develop SLE, most patients have a self-limited disease. Importantly, KFD can have skin manifestations resembling cutaneous lupus. Therefore, the diagnosis of SLE should be predicated on a complete rheumatologic workup and not on the constellation of skin disease and lymphadenitis. Nonetheless, as our exceedingly rare case illustrates, patients who do not initially meet diagnostic criteria for SLE require dermatologic follow-up. We present a young adult woman who had a remote history of KFD and later presented with combined features of discoid lupus and lupus erythematosus panniculitis (LEP). On subsequent rheumatologic workup, she fulfilled criteria for SLE. We discuss the differential diagnosis of both KFD and LEP and emphasize how strong communication among dermatologists and other healthcare providers is essential in the management of patients with KFD.

Sarcoidosis with small syringotropic granulomas presenting clinically as a pigmented purpuric dermatosis: Inconspicuous clinical and histopathological clues to systemic illness.

Sarcoidosis is a multisystem granulomatous disease with a myriad of clinical manifestations and a predilection to involve the lungs, eyes, lymph nodes, and skin. A 38-year-old man presented to dermatology with a history of progressive dyspnea, pulmonary consolidations on chest X-ray, and hilar adenopathy on computed tomography scan. Skin exam revealed asymptomatic, yellow to brown macules on the right lower extremity. Biopsy of a lesion showed diminutive syringotropic granulomas and perivascular hemosiderin; stains for bacteria, mycobacteria, and fungi were negative. Subsequent fine needle aspiration of a hilar mass revealed non-necrotizing epithelioid granulomas further supporting a diagnosis of sarcoidosis. The patient was placed on systemic steroids and had improvement of his pulmonary symptoms and stabilization of his hilar lymphadenopathy without resolution of his pigmented purpuric dermatosis (PPD) like lesions. Only three prior cases of syringotropic sarcoidosis have been reported; however, the biopsies had revealed conspicuously large granulomas in contrast with the small granulomas in our case, and none of the prior patients had clinical examination findings that mimicked PPD. Recognition of rare dermatologic and histopathological appearances of sarcoidosis is paramount as cutaneous sarcoidosis may be the harbinger of a systemic illness, which requires a timely diagnosis.

Tumor-stage mycosis fungoides in palmoplantar localization with large-cell transformation and partial CD30 expression shows complete response to brentuximab vedotin.

Mycosis fungoides in palmoplantar localization (MFPP) is a rare variant of MF that is confined to the hands and feet. Patients commonly receive treatment over many years for suspected palmoplantar dermatitis before the diagnosis is made. Most MFPP patients remain at patch or plaque stage, and often respond to treatment with radiotherapy. Herein, we describe a 77-year-old man who suffered 6 years of hand and foot dermatitis that failed multiple treatments, most notably TNF-α inhibitors and mycophenolate mofetil. He eventually developed a tumor on the hand, which was biopsied to reveal a dense dermal infiltrate of large lymphocytes (CD3+/CD4-/CD8-/TCR-BetaF1+/partial CD30+). A subsequent biopsy of an eczematous patch from his hand revealed an epidermotropic and syringotropic infiltrate comprised of smaller lymphocytes with a concordant immunophenotype and matching clonal peak with TCR gene rearrangement. He was diagnosed with MFPP and started on radiotherapy with a modest response; therefore, a decision was made to start brentuximab vedotin, which resulted in a complete response. MFPP is an exceedingly rare variant of MF that can show large-cell transformation and progress in stage. We highlight a possible association between disease progression and immunosuppressants and the potential role for treatment with brentuximab.

The many masks of cutaneous Lyme disease.

Early cutaneous Lyme disease, erythema migrans, may show different histopathologic patterns. The intent of this case series is to raise awareness of these findings to prevent misdiagnosis and keep this entity in the differential. Erythema migrans develops after a tick bite and subsequent infection with the spirochete, Borrelia burgdorferi. It most commonly manifests as a solitary, annular lesion with a bull's-eye appearance. Classic histopathologic findings include superficial and deep perivascular and interstitial lymphocytic infiltrates mixed with plasma cells and eosinophils. We identified and reviewed eight cases of early erythema migrans. Each patient had confirmed B. burgdorferi IgM seropositivity and IgG seronegativity. Histopathologic evaluation of these biopsies reveals a diversity of patterns. Seven of eight cases show sparse to mild perivascular and interstitial mixed infiltrate of variable amount of lymphocytes, eosinophils, neutrophils and plasma cells, with only one case showing a dense inflammatory infiltrate. Epidermal changes such as spongiosis and interface change are seen in some cases. Additionally, perineural lymphocytic infiltrate is seen in one case, periadnexal infiltrate in four cases and pigment incontinence in one case. Based on variable histopathologic findings, it is important to consider erythema migrans in the differential diagnosis for prompt diagnosis and treatment.