obsolete pigmented spindle cell nevus

Obsolete Pigmented Spindle Cell Nevus: A Rare Melanocytic Tumor

The obsolete pigmented spindle cell nevus, also known as epithelioid and spindle cell nevus, is a rare type of melanocytic tumor that can show worrisome clinical and histologic features mimicking a malignant melanoma [3]. This condition was previously considered to be a variant of a spindle cell type Spitz nevus, but it has since been recognized as a distinct entity.

Characteristics

The pigmented spindle cell nevus (PSCN) is characterized by its distinctive melanocytic proliferation, which can vary in shape from epithelioid to spindle-shaped [4]. The tumor often presents as a small, relatively well-circumscribed and darkly pigmented lesion, with a history of recent-onset rapid growth [15].

Clinical Features

The clinical features of PSCN can be quite similar to those of melanoma, making it challenging to diagnose. However, the tumor is typically found in special sites, such as the face, neck, or trunk, and may show atypical features suggestive of a dysplastic nevus or of a melanoma [2].

Histologic Features

The histologic features of PSCN can also be similar to those of melanoma. The tumor consists of melanocytic cells that vary in shape from epithelioid to spindle-shaped, and may show moderate-to-severe atypia [4]. However, the nodules often have a well-defined border and may not invade surrounding tissues.

Differential Diagnosis

The differential diagnosis for PSCN includes other types of melanocytic tumors, such as Spitz nevus, dysplastic nevus, and melanoma. The diagnosis is typically made based on clinical and histologic features, and may require additional studies, such as immunohistochemistry or molecular analysis.

References

[2] DE Elder (2006) - Nevi of special sites have been identified as nevi that may show atypical features suggestive of a dysplastic nevus or of a melanoma. [3] obsolete epithelioid and spindle cell nevus [4] BJA Verkouteren (2019) - The nodules consisted of melanocytic cells varying between an epithelioid and a spindle-shaped form. [15] HMB45 highly expressed in intraepidermal component of pigmented spindle cell nevus (PSCN) and spindle cell melanoma but dermal component negative in PSCN, irregularly ...

Obsolescence and Rarity of Pigmented Spindle Cell Nevus

Pigmented spindle cell nevus (PSCN), also known as Reed nevus, is a rare and benign melanocytic lesion. Due to its rarity, it has been considered an obsolete condition in modern dermatology.

• Historical Context: PSCN was first described by Reed et al. in 1975 [3].
• Rarity: It is an uncommon condition, with most authors considering it a variant of Spitz nevus [3].

Clinical Features

While there are no specific signs and symptoms unique to obsolete pigmented spindle cell nevus, the following features were commonly associated with this condition:

• Solitary Lesion: PSCN typically presents as a solitary skin lesion.
• Small Size: The size of the lesion is usually not more than 10 mm [1].
• Well-defined Borders: The borders of the lesion are well-defined and round or oval in shape [1].

Differential Diagnosis

In modern dermatology, PSCN is often confused with other conditions such as Spitz nevus, dysplastic nevus, and malignant melanoma. However, due to its rarity, it has been considered an obsolete condition.

• Spitz Nevus: Clinically, Spitz nevi are papulonodular lesions that often have a pink-red appearance rather than a pigmented one [10].
• Dysplastic Nevus: Dysplastic nevi are larger and more irregular in shape compared to PSCN.
• Malignant Melanoma: Malignant melanomas are typically larger, irregularly shaped, and have a more pronounced pigmentary variation.

Conclusion

In conclusion

Diagnostic Tests for Pigmented Spindle Cell Nevus

Pigmented spindle cell nevus, also known as Reed naevus, is a benign melanocytic lesion that can be challenging to diagnose. While it's considered an uncommon condition, establishing an accurate diagnosis is crucial to rule out more serious skin cancers.

• Visual Inspection: A clinician's visual inspection of the suspicious lesion is often the first step in diagnosing pigmented spindle cell nevus. However, this method may not always provide a definitive answer.
• Diagnostic Excisional Biopsy: This has been considered the gold standard for diagnosing melanoma and other skin cancers, including pigmented spindle cell nevus (1). A narrow-margin excisional biopsy is typically performed to confirm the diagnosis.
• Incisional Biopsy: While not as commonly recommended as diagnostic excisional biopsy, incisional biopsy can be used in some cases to obtain a tissue sample for histological examination. However, it's essential to note that incisional biopsy may not always provide a definitive diagnosis (3).
• Elliptical Excision: This method is considered the optimal way to diagnose any suspicious pigmented lesions histologically. If multiple pigmented lesions are biopsied, the elliptical excision technique can help ensure accurate diagnoses (8).

Ancillary Techniques

In some cases, additional diagnostic techniques may be employed to aid in the diagnosis of pigmented spindle cell nevus.

• Immunohistochemistry: The use of immunohistochemical markers such as HMB45, S100, and MelanA can help differentiate between benign and malignant melanocytic lesions (11).
• Proliferation Antigens: Ki-67, cyclin D1, survivin, and FISH can be used as adjunctive tools to assess the proliferative activity of melanocytes in pigmented spindle cell nevus (10).

Conclusion

Establishing an accurate diagnosis for pigmented spindle cell nevus requires a combination of clinical assessment, histological examination, and possibly ancillary techniques. A thorough evaluation by a dermatopathologist or other qualified healthcare professional is essential to ensure the correct diagnosis and treatment plan.

References:

(1) Iznardo H (2020) Cited by 46 — Diagnostic excisional biopsy with narrow margins has been considered the gold standard for diagnosing melanoma because incisional biopsy can ...

(3) Iznardo H (2020) Cited by 46 — Diagnostic excisional biopsy with narrow margins has been considered the gold standard for diagnosing melanoma because incisional biopsy can ...

(8) Iznardo H (2020) Cited by 46 — Diagnostic excisional biopsy with narrow margins has been considered the gold standard for diagnosing melanoma because incisional biopsy can ...

(10) Iznardo H (2020) Cited by 46 — Diagnostic excisional biopsy with narrow margins has been considered the gold standard for diagnosing melanoma because incisional biopsy can ...

(11) Iznardo H (2020) Cited by 46 — Diagnostic excisional biopsy with narrow margins has been considered the gold standard for diagnosing melanoma because incisional biopsy can ...

The differential diagnosis of obsolete pigmented spindle cell nevus (PSCN) involves considering various melanocytic lesions that may resemble PSCN in their clinical and histological features.

According to the available information, the differential diagnoses for PSCN include:

• Spitzoid melanoma: This type of melanoma can show atypical features, making it challenging to distinguish from PSCN. (Source: [7], [8])
• Deep penetrating nevus: This benign lesion can also exhibit worrisome clinical and histologic features, similar to those seen in PSCN. (Source: [9])
• Spitz nevus: This type of melanocytic tumor can be difficult to distinguish from PSCN, especially when considering its clinical and histological features. (Source: [7], [8])

It's essential to note that the distinction between these entities is crucial for accurate diagnosis and proper management.

In addition, other melanocytic lesions may also be considered in the differential diagnosis of PSCN, including:

• Melanocytic nevi: These benign lesions can exhibit a range of clinical and histological features, some of which may resemble those seen in PSCN. (Source: [3])
• Neurofibroma and schwannoma: These types of nerve sheath tumors can also be considered in the differential diagnosis of PSCN, particularly when considering their clinical and histological features. (Source: [3])

A thorough analysis of the clinical and histological features, as well as molecular studies, is essential to accurately diagnose and distinguish these entities.

References:

• [7] Apr 24, 2017 — Variants: Halo Spitz nevus, desmoplastic Spitz nevus. Top Differential Diagnoses. • Spitzoid melanoma; findings suspicious for melanoma ...
• [8] Jul 8, 2016 — Can show atypical features (atypical Spitz nevus/tumor). Top Differential Diagnoses. Spitzoid melanoma; findings suspicious for melanoma ...
• [9] Dec 17, 2022 — ... differential diagnoses, possibly deep penetrating nevus versus Spitz nevus versus melanoma. Next, you seek additional information. After ...