Mycobacterial Spindle Cell Pseudotumor (MSP): A Case Report.

Mycobacterial spindle cell pseudotumor (MSP) is a rare proliferation of spindle-shaped histiocytes that occurs most frequently in lymph nodes but has also been documented in the skin, soft tissue, abdomen, and other sites. These lesions contain acid-fast mycobacteria, most commonly Mycobacterium avium complex. Fewer than 10 cases of cutaneous MSPs have been published, and most have occurred in immunocompromised patients, either due to human immunodeficiency virus (HIV) infection or immunosuppressive medications. The differential diagnosis includes Kaposi's sarcoma and other spindle cell neoplasms, which can be distinguished based on histology and special stains. We present the case of a 76-year-old man with HIV infection who presented with a diffuse rash on his arms and legs. A pretibial biopsy was performed and revealed tubercular MSP.

A case report of granulomatous lymphomatoid papulosis.

Lymphomatoid papulosis is a chronic CD30-positive cutaneous lymphoproliferative disorder that is characterized by recurring red-brown necrotic papules. It exhibits a wide spectrum of histopathologic findings and is often associated with cutaneous T-cell lymphomas. Six different histological subtypes have been classified by the WHO, but there is limited understanding regarding rare histopathologic variants. We describe a 51-year-old man who presented with recurring, necrotic papules for 6 years that progressed to involve the face, scalp, trunk, axilla, and scrotum. Histopathology demonstrated sarcoidal granulomas, along with a CD30-positive T cell infiltrate which demonstrated clonality by T cell receptor gamma gene rearrangement. A diagnosis of lymphomatoid papulosis associated with granulomas was established based on the clinical and histopathologic presentation. The clinical understanding of granulomatous lymphomatoid papulosis is limited in the available literature and more awareness of this histopathologic variant is required for accurate classification of this disorder.

Cutaneous solitary fibrous tumor: Report of three cases with review of histopathological mimics.

Solitary fibrous tumor (SFT) is a relatively uncommon spindle cell mesenchymal neoplasm that is most often based on the pleura but may rarely arise in extrapleural locations, including the skin. Herein, we describe three cases of cutaneous SFTs. SFT is characterized by epithelioid and spindle cells arranged in random patterns with focal prominent stromal collagen and pericytomatous vessels. Immunohistochemical evaluation is required for definitive distinction of SFT from other benign and malignant cutaneous spindle cell neoplasms. Although aggressive biologic behavior is uncommon, accurate diagnosis of it is required for prognostication and counseling. CD34, bcl-2, and CD99 stains are positive in SFT, but not specific. STAT6 is the most sensitive and specific immunohistochemical marker to confirm diagnosis of SFT.

Knuckle pads: an ancient disease frequently misdiagnosed because of minimal modern attention.

Knuckle pads are benign painless papules and nodules that most commonly appear on the extensor surfaces of the proximal interphalangeal joints. Knuckle pads are frequently misdiagnosed due to their location overlying joints, which can lead to costly interventions and patient discomfort for a relatively harmless condition. We describe a 44-year-old woman who presented with mildly painful nodules on multiple bilateral proximal interphalangeal joints. The patient did not have a family history of fibromatosis and the rheumatoid factor was negative. Histology showed mild epidermal hyperkeratosis, papillomatosis, and acanthosis with a deep dermal, poorly circumscribed, proliferative nodule made of spindled myofibroblasts without cytological atypia. The diagnosis of knuckle pads was established based on the clinical and morphological presentation of the nodules. Treatment with intralesional triamcinolone acetonide injection produced significant clinical improvement. Our findings highlight the challenging diagnosis of knuckle pads and the importance of increasing the familiarity of knuckle pads in modern medical practice.

Reactive angioendotheliomatosis associated with antiphospholipid syndrome.

Reactive angioendotheliomatosis (RAE) is an uncommon, benign, antiproliferative condition associated with systemic diseases that may cause occlusion or inflammation of the vascular lumina. A link between antiphospholipid syndrome (APS) and RAE has been reported a few times in the literature. Herein, we present a unique case of RAE diagnosed in a patient with primary APS who was well-managed on warfarin and rituximab with no recent thrombotic events. As RAE can precede or follow a diagnosis of APS, the presence of the condition indicates a need to workup for APS and to ensure those with the condition are adequately anticoagulated. However, as demonstrated in this case, the condition can still occur in patients who are adequately anticoagulated.

Sclerosing perineurioma: a rare benign tumor in a pediatric patient.

A 15-year-old boy presented to outpatient dermatology clinic for evaluation of a lesion on the hand. Originally small and asymptomatic, the lesion had rapidly enlarged in the six months prior to evaluation. A shave biopsy was performed and histopathologic evaluation demonstrated a well-circumscribed nodular proliferation of dense, bland, epithelioid to spindle cells on a fibrillary background. Tumor cells were diffusely epithelial membrane antigen (EMA) positive; S100 and Melan-A were negative. These findings are consistent with a diagnosis of sclerosing perineurioma. This case illustrates the presentation of sclerosing perineurioma in a pediatric patient and we review the pertinent pathologic and immunohistochemical findings necessary for diagnosis. It is imperative to distinguish this entity from other soft tissue tumors on the hand, both benign and malignant, to avoid overly aggressive surgical intervention.

Autologous Fat Transfer for Scar Prevention and Remodeling: A Randomized, Blinded, Placebo-controlled Trial.

Autologous fat transfer-also referred to as fat grafting-has been reported to provide beneficial effects to overlying scar and skin. Despite procedural frequency, there is a paucity of high-level evidence guiding the surgeon in technique, patient selection, and efficacy. METHODS: A multicenter, double-blinded, randomized, internally placebo-controlled trial was performed with an aim to qualitatively and quantitatively evaluate the impact of autologous fat transfer on the quality of overlying scar tissue. Fat-grafted scars were evaluated and compared with paired, saline-injected "control" scars. Subjective and objective metrics were evaluated in treated sites for 12 months after treatment. RESULTS: Blinded qualitative results demonstrated a statistically significant improvement in scar quality over time in fat-grafted scars. However, these improvements were not found to be statistically different from changes noted in scars treated with saline. In addition, objective metrics did not statistically differ between saline-injected and autologous fat-grafted scars. CONCLUSIONS: Our results demonstrate that autologous fat grafting can improve the qualitative profile of a scar from both the patient and observer perspectives. However, there was no difference in improvement when compared with scars that were treated with saline in a randomized and blinded fashion. These results demonstrate that any improvements in scar quality related to fat grafting are also achieved using saline and suggest that mechanisms other than cell activity may be at play. Additional randomized, blinded, placebo-controlled trials are required to either corroborate or contest the putative beneficial effect(s) of adipose tissue on scar remodeling.

Lichen planus-like keratosis: clinicopathological evaluation of 1366 cases.

BACKGROUND: Lichen planus-like keratosis (LPLK) is a frequent skin lesion usually biopsied to rule out basal cell carcinoma (BCC). Because of overlapping histopathological characteristics, LPLK is frequently muddled with lichen planus (LP), lichenoid actinic keratosis (LAK), and lupus erythematosus (LE). OBJECTIVE: To investigate the clinical and histopathological characteristics of LPLK. METHODS: A clinicopathologic review was performed of all LPLK cases (1366) signed in one calendar year in a busy academic practice. RESULTS: LPLK occurs mostly as a single lesion (97%) with the chest (41.4%) being the most common site. It is almost equally present in women and men (51.5%-48.5%). The most common clinical concern (65%) is basal cell carcinoma. Parakeratosis, red blood extravasation, and presence of dermal eosinophils and plasma cells, usually not seen in lichen planus, are helpful signs to suggest LPLK but are seen only in a minority of cases. CONCLUSION: Clinicopathologic correlation is necessary to diagnose lichen planus-like keratosis, as the most consistent feature is a clinical history of a lesion/neoplastic process rather than an inflammatory process. There are histopathologic features that can help distinguish lichen planus-like keratosis from lichen planus; however, these features are nonspecific and lacking in almost half of the cases.

An amelanotic nail bed melanoma presenting as persistent onychodystrophy.

Nail apparatus melanomas are rare and may present with a wide variety of clinical presentations. In particular, the amelanotic subtype can pose a diagnostic challenge, often leading to a poor prognosis related to a delayed diagnosis. We report a 69-year-old man with an unusual subungual amelanotic melanoma presenting as a persistent single nail dystrophy that was repeatedly treated as onychomycosis. Owing to the delayed diagnosis of the melanoma and to minimize recurrence risk, the patient underwent a partial amputation of his left thumb.

Scabies Associated with Granulomatous Dermatitis.

Scabies is a relatively common parasitic infection, which has sometimes been associated with the formation of granuloma annulare. We report the case of an 86-year-old female who developed a non-necrotizing granulomatous dermatitis after a scabies infestation. This case highlights the importance of considering scabies in the differential diagnosis when granulomatous dermatitis is noted histologically that cannot be explained by other causes.

Pseudoxanthoma elasticum-like changes in nonuremic calciphylaxis: Case series and brief review of a helpful diagnostic clue.

Calciphylaxis is a rare syndrome of vascular calcification with thrombosis that occurs most often in patients with end-stage renal disease, and it frequently portends a guarded prognosis. Rarely, nonuremic calciphylaxis (NUC) may occur; in this context, a strongly supportive histology is crucial in establishing the diagnosis. Herein, we describe 2 cases of NUC associated with pseudoxanthoma elasticum-like changes, identified in both initial nondiagnostic and subsequent diagnostic biopsy specimens. This unusual but helpful histologic finding may support the early diagnosis and treatment of a potentially life-threatening disease in the context of subtle histopathologic vascular changes or in the absence of classic clinical or laboratory findings.

Purely cutaneous rosai-dorfman disease with immunohistochemistry.

BACKGROUND: The cutaneous form of Rosai-Dorfman disease (RDD) is a rare entity that manifests solely with skin papules or nodules and does not present with the usual myriad of symptoms of classical RDD. AIMS: To analyze the most recent publications regarding cutaneous RDD to point out updated, relevant aspects regarding future directions for clinical recognition and management. To identify histopathologic and immunohistochemical findings in skin lesions that permit diagnosis. MATERIALS AND METHODS: We present a case of a gentleman with a history of multiple lipomas with a new solitary nodule on physical exam; microscopic examination shows the typical findings of RDD with the associated diagnostic immunohistochemical profile, as well as the expected finding of histiocytes engulfing other intact inflammatory cells. RESULTS: Our patient was managed with surgical excision of the entire lesion, one of the several available treatment options. Long-term follow-up 2 years later did not reveal any complications, recurrences, or new lesions. CONCLUSION: The diagnosis of cutaneous RDD is differentiated from other histiocytic conditions by the combination of clinical findings accompanied by histopathologic and immunohistochemical confirmation.